Note: Descriptions are shown in the official language in which they were submitted.
CA 02617291 2008-01-24
74570-101D
SECONDARY BATTERY
This is a divisional application of Canadian
Patent Application No. 2,337,590 filed on February 20, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a stable secondary
battery with a higher energy density and to an active
material used therein. This invention includes several
embodiments and the subject matter of this divisional
application is restricted to such secondary battery and
active material in which a reactant or product of an
electrode reaction comprises a nitrogen radical compound
having an aminotriazine group or a nitrogen radical polymer
compound having, as a repeating unit, an aminotriazine
structure. However, it should be understood that the
expression "this invention" or the like encompasses all the
embodiments disclosed in both this divisional application
and the parent application.
2. Description of the Prior Art
As markets for a note-type personal computer and a
mobile telephone have been rapidly expanded, there have been
increased needs to a small and large-capacity secondary
battery with a higher energy density used in these devices.
To satisfy the needs, a secondary battery has been
developed, which utilizes an electrochemical reaction
associated with charge transfer on alkali-metal ions as a
charge carrier such as lithium ions. Among others, a
lithium-ion secondary battery has been used in a variety of
electronic devices as a stable and large-capacity secondary
battery with a higher energy density.
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74570-1O1D
Such a lithium-ion secondary battery uses a
transition-metal oxide containing lithium in a positive
electrode (cathode) and carbon in a negative electrode
(anode) as active materials, and performs charge and
discharge utilizing insertion in and elimination from these
active materials.
However, since the lithium-ion secondary battery
uses
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CA 02617291 2008-01-24
570-101
a metal oxide with a large specific gravity particularly in
a positive electrode, it has an insufficient secondary
battery capacity per a unit weight. There have been,
therefore, attempts for developing a large-capacity
secondary battery using a lighter electrode material.
U.S. Patent 4,833,048 and JP Patent 2,715,778 have disclosed a
secondary battery using an organic compound having a
disulfide bond in a positive electrode, which utilizes, as
a principle of a secondary battery, an electrochemical
oxidation-reduction reaction associated with formation and
dissociation of a disulfide bond. The secondary battery
uses electrode materials comprising elements having a
smaller specific gravity such as sulfur and carbon as main
components. Although these materials are effective to some
degree in providing a large-capacity secondary battery with
a higher energy density, it has a small efficiency in
reformation of a dissociated bond and exhibits insufficient
stability in a charge or discharge condition.
Furthermore, there has been suggested a secondary
battery also utilizing an organic compound, i.e., a
secondary battery using a conductive polymer as an
electrode material. It is a secondary battery whose
principle is doping and undoping reactions of electrolyte
ions on the conductive polymer. The doping reaction as used
herein is a reaction of stabilizing excitons such as
charged solitons and polarons generated by oxidation or
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reduction of a conductive polymer by counter ions. On the
am , ~
other hand, a'undoping reaction as used herein refers to a
reaction which is opposite to the above reaction and in
which excitons stabilized by counter ions are
electrochemically oxidized or reduced. US Patent 4,442,187
has disclosed a secondary battery using such a conductive
polymer as a positive electrode or negative electrode
material. The secondary battery is constituted with
elements with a lower specific gravity such as carbon and
nitrogen, and thus has been expected to be developed as a
large-capacity secondary battery. A conductive polymer,
however, has a property that excitons generated by
oxidation or reduction are delocalized over a wide region
of 8-electron conjugated system and interacted with each
other. It results in a limitation to a concentration of
excitons generated, and therefore, to a capacity of a
secondary battery. Thus, a secondary battery using a
conductive polymer as an electrode material is effective to
some degree in terms of weight reduction, but is not
adequately effective in terms of increase in a capacity.
As described above, there have been various proposals
for a secondary battery which does not use a transition-
metal containing active material, in an attempt to achieve
a large-capacity secondary battery. There have been,
however, provided no stable secondary batteries with a
higher energy density and a large capacity.
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As described above, in a lithium-ion secondary
battery using a transition metal oxide as a positive
electrode, a specific gravity of the element is so high
that it has been theoretically difficult to prepare a
secondary battery with a larger capacity than that
currently used. An objective of this invention is,
therefore, to provide a novel stable secondary battery with
a higher energy density and a larger capacity.
SUMMARY OF THE INVENTION
To solve the above problems, this invention provides:
[1] a secondary battery comprising at least a
positive electrode, a negative electrode and an electrolyte,
wherein an active material in at least one of the positive
electrode and the negative electrode contains a radical
compound;
[2] a secondary battery comprising at least a
positive electrode, a negative electrode and an electrolyte,
wherein an active material in at least one of the positive
electrode and the negative electrode is a radical compound;'
[3] a seco,ndary battery comprising at least a
positive electrode, a negative electrode and an electrolyte,
wherein an active material in at least one of the positive
electrode and the negative electrode consists of two or
more materials, at least one of which is a radical
compound;
[4] a secondary battery utilizing an electrode
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reaction of an active material, wherein the electrode
reaction in at least one of the positive electrode and the-
negative electrode is that where a reactant or product is a
radical compound.; or
[5] a secondary battery utilizing an electrode
reaction of an active material, wherein two or more
electrode reactions occur in at least one of the positive
electrode and the negative electrode and at least one of
the reactions is that where a reactant or product is a
radical compound.
In the present invention, a positive electrode means
a cathode and a negative electrode means an anode.
In the above secondary battery, the active material
may be a positive electrode active material.
In the above secondary battery, the electrode
reaction may be that in the positive electrode.
In the above secondary battery, the electrode
reaction in the positive electrode may be a discharge
reaction in which the radical compound is a reactant.
In the above secondary battery, the electrode
reaction in the positive electrode may be a discharge
reaction in which the radical compound is a product.
In the above secondary battery, the discharge
reaction may be that forming a bond between the radical
compound and an electrolyte cation.
In the above secondary battery, the discharge
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reaction may be that cleaving a bond between the radical
compound and an electrolyte anion.
In the above secondary battery, the electrolyte
cation may be a lithium ion.
In the above secondary battery, the radical compound
may have a spin concentration of 1021 spins/g or more.
In the above secondary battery, the radical compound
may be a neutral radical compound.
In the above secondary battery, the radical compound
may be a stable radical compound.
In the above secondary battery, examples of the
radical compound include the followings:
N-O =
(A1)
XN
/N-O =
X2
(A2)
wherein X1 and X2 are a substituent containing at
least one of an aliphatic group, an aromatic group, hydroxy,
alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano, amino,
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nitro, nitroso, halogen or hydrogen, provided that when X1
and X2 contain an aliphatic group, the aliphatic group may-
be saturated or unsaturated, substituted or unsubstituted,
and straight, cyclic or branched, and may contain at least
one of oxygen, nitrogen, sulfur, silicon, phosphorous,
boron and halogen atoms; when X1 and X2 contain an aromatic
group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X1 and X2 contain hydroxy, the hydroxy may form
a salt with a metal atom; when X1 and X2 contain alkoxy,
aldehyde, carboxyl, alkoxycarbonyl, cyano, amino, nitro or
nitroso, these substituents may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicone, phosphorous, boron and halogen
atoms; Xl and X2 may be the same or different; and Xl and X2
taken together may form a ring;
x\-'~
R
~N-O = (A3)
wherein R is alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
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containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl',
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X may form a ring;
and the alkyl R may be tert-butyl;
X 1\
/N-O
X2 Rl
Rz
(A4)
wherein R1 and R2 are alkyl which may be substituted
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or unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,'
phosphorous, boron and halogen atoms; R1 and R2 may be the
same or different; X1 and X2 are a substituent containing
at least one of an aliphatic group, an aromatic group,
hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro, nitroso, halogen or hydrogen, provided that
when X1 and X2 contain an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X1 and X2
contain an aromatic group, the aromatic group may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; when X1 and X2 contain hydroxy, the
hydroxy may form a salt with a metal atom; when X1 and X2
contain alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro or nitroso, these substituents may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; X1 and X2 may be the same or different;
and X1 and X2 may form a ring; and both of the alkyls R1 and
R2 may be methyl;
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R1
X RZ
C~
-0
XZ R3
R4
(A5)
wherein R1 to R4 are alkyl which may be substituted
or unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; R1 to R4 may be the
same or different; X1 and X2 are a substituent containing
at least one of an aliphatic group, an aromatic group,
hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro, nitroso, halogen or hydrogen, provided that
when X1 and X2 contain an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X1 and X2
contain an aromatic group, the aromatic group may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; when X1 and X2 contain hydroxy, the
hydroxy may form a salt with a metal atom; when X1 and X2
CA 02617291 2008-01-24
contain alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro or nitroso, these substituents may be
substituted or unsubstituted and may contain at least-one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; X1 and X2 may be the same or different;
and X1 and X2 may form a ring; and all of the alkyls R1 to
R4 may be methyl.
The radical compound may be the nitroxyl radical
compound represented by general formula (A6) where the
nitrogen atom in the nitroxyl radical group is bound to at
least one aryl:
x \
N_' Q '
A>"~
(A6)
wherein Ar is aryl which may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; X is a substituent containing at least one of an
aliphatic group, an aromatic group, hydroxy, alkoxy,
aldehyde, carboxyl, alkoxycarbonyl, cyano, amino, nitro,
nitroso, halogen or hydrogen, provided that when X contains
an aliphatic group, the aliphatic group may be saturated or
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unsaturated, substituted or unsubstituted, and straight,
cyclic or branched, and may contain at least one of oxygerr,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains an aromatic group, the aromatic
group may be substituted or unsubstituted and may contain
at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains
hydroxy, the hydroxy may form a salt with a metal atom;
when X contains alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro or nitroso, the substituent may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; X may form a ring; and the aryl may be
substituted or unsubstituted phenyl.
The radical compound may be the compound forming
substituted or unsubstituted heterocycle, represented by
general formula (A7):
[X) n N- 0 =
(A7}
wherein X is carbon, oxygen, nitrogen, sulfur,
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silicon, phosphorous or boron atom, provided that X may be
the same or different; X may be bound via saturated or
unsaturated bonds; X may form a bond with any substituent;
this compound may be a polymer which may be straight,
cyclic or branched; and n is an integer of 2 to 10 both
inclusive.
The above radical compound may be the nitroxyl
radical compound having a piperidinoxyl ring structure,
represented by general formula (A8):
R1
R2
X Q
R3
R4
(A8)
where R1 to R4 are alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
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that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
The above radical compound may be the nitroxyl
radical compound having a pyrrolidinoxyl ring structure
represented by general formula (A9):
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x R2
N o
R3
R4
(A9)
where R1 to R4 are alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
CA 02617291 2008-01-24
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
The above radical compound may be the nitroxyl
radical compound having a pyrrolinoxyl ring structure
represented by general formula (A10):
1
~ R2
N-0
R3
R4
(A 1 0)
where R1 to R4 are alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
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contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
The above radical compound may be the
nitronylnitroxide compound represented by general formula
(All):
X1\
N-- O p
X3 ~ /NO
2
(A11)
where X1 to X3 are a substituent containing at least
one of an aliphatic group, an aromatic group, hydroxy,
alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano, amino,
nitro, nitroso, halogen or hydrogen, provided that when X1
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to X3 contain an aliphatic group, the aliphatic group may
be saturated or unsaturated, substituted or unsubstituted,-
and straight, cyclic or branched, and may contain at least
one of oxygen, nitrogen, sulfur, silicon, phosphorous,
boron and halogen atoms; when X1 to X3 contain an aromatic
group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X1 to X3 contain hydroxy, the hydroxy may form
a salt with a metal atom; when X1 to X3 contain alkoxy,
aldehyde, carboxyl, alkoxycarbonyl, cyano, amino, nitro or
nitroso, these substituents may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; Xl to X3 may be the same or different; and Xl to X3
may form a ring.
In the above secondary battery, the radical compound
may be a polymer.
The polymer may be, for example, a polymer having a
polyacetylene or polyphenylene-vinylene chain as a main
chain.
In the above secondary battery, the radical compound
may comprise an oxy radical compound.
The oxy radical compound may be, for example, an
aryloxy radical compound.
Examples of the aryloxy radical compound may include
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those having an arylpolyoxy radical group, a tert-butyl
group or a di-tert-butylphenoxy radical group.
In the above secondary battery, the oxy radical
compound may be that containing a semi-quinone.
In the above secondary battery, the oxy radical
compound may be a compound which is poorly soluble in a
basic solvent.
In the above secondary battery, the oxy radical
compound may be a polymer radical compound.
Examples of the polymer radical compound may include
compounds having a polyolefin, polyacetylene or
polyphenylene structure. In particular, preferably used
polymers may be those having a five-membered aromatic
heterocyclic structure and polymer compounds having a
three-dimensional network structure.
In the secondary battery, the radical compound may
comprise a compound having a radical on a nitrogen atom.
In the secondary battery, the radical compound may
comprise a compound having a radical on a nitrogen atom in
an oxidized form.
In the secondary battery, the radical compound may
comprise a compound having a radical on a nitrogen atom in
a reduced form.
Examples of the compound having a radical on a
nitrogen atom may include:
a compound having a radical on a trivalent pherdazyl
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group represented by chemical formula (Cl) or a tetravalent
pherdazyl group represented by chemical formula C(2);
-- f
N-N
(C 1)
N-N
~
N-N
~ (C Z)
.
N-N
~
a compound having a triphenylpherdazyl group
represented by chemical formula (C3) or (C4);
N-N
(c 3)
NN
CA 02617291 2008-01-24
I\
(C4)
N-- a compound having a radical on a trivalent hydrazyl
group represented by chemical formula(C5);
' =
N-N-- ( G 5)
/
a compound having a radical on a trivalent hydrazyl
group represented by chemical formula (C6);
Rl R3
N-- ~ R4 (C 6)
RZ
R5
where R1 to R5 independently represent hydrogen,
substituted or unsubstituted aliphatic or aromatic
hydrocarbon, halogen, hydroxy, nitro, nitroso, cyano,
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alkoxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, acyl or
carboxy.
A compound having a radical on a nitrogen atom may be
diphenylpicrylhydrazyl.
A compound having a radical on a nitrogen atom may be
a compound having an aminotriazine structure represented by
general formula (C7):
R6
N (C7)
N N
where R6 represents hydrogen, substituted or
unsubstituted aliphatic or aromatic hydrocarbon, halogen,
hydroxy, nitro, nitroso, cyano, alkoxy, aryloxy,
alkoxycarbonyl, aryloxycarbonyl, acyl, carboxy or oxo
radical.
The compound having a radical on a nitrogen atom may
be a polymer. For example, it may be a polymer having the
aminotriazine structure represented by general formula (C7)
as a repeating unit.
This invention also provides the following active
materials for a secondary battery:
[1] an active material for a secondary battery
comprising a radical compound;
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CA 02617291 2008-01-24
[2] an active material for a secondary battery
involved in an electrode reaction in the secondary battery',
wherein a reactant or product from the active material in
the electrode reaction is a radical compound.
In the above secondary battery, a spin concentration
of the radical compound is 1021 spins/g or more.
The active material for a secondary battery may be
used in a positive electrode in the secondary battery.
In the above active material for a secondary battery,
the radical compound may contain a nitroxyl radical
compound having the functional group represented by
chemical formula (Al).
/N-0 =
(A1)
In the above active material for a secondary battery,
the radical compound may contain the nitroxyl radical
compound represented by general formula (A2):
X N
X N-0
z /
(A2)
wherein X1 and X2 are a substituent containing at
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CA 02617291 2008-01-24
least one of an aliphatic group, an aromatic group, hydroxy,
alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano, amino,
nitro, nitroso, halogen or hydrogen, provided that when X1
and X2 contain an aliphatic group, the aliphatic group may
be saturated or unsaturated, substituted or unsubstituted,
and straight, cyclic or branched, and may contain at least
one of oxygen, nitrogen, sulfur, silicon, phosphorous,
boron and halogen atoms; when X. and X2 contain an aromatic
group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X1 and X2 contain hydroxy, the hydroxy may form
a salt with a metal atom; when X1 and X2 contain alkoxy,
aldehyde, carboxyl, alkoxycarbonyl, cyano, amino, nitro or
nitroso, these substituents may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicone, phosphorous, boron and halogen
atoms; X1 and X2 may be the same or different; and X1 and X2
taken together may form a ring.
In the above active material for a secondary battery,
the radical compound may be the nitroxyl radical compound
in which a nitrogen atom in the nitroxyl radical is'bound
to at least one alkyl, represented by general formula (A3):
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X
N- O =
R/
(A 3)
wherein R is alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
CA 02617291 2008-01-24
In the above active material for a secondary battery,
the alkyl group may be tert-butyl;
In the above active material for a secondary battery,
the radical compound may be the nitroxyl radical compound
in which a nitrogen atom in the nitroxyl radical is bound
to at least two alkyls, represented by general formula
(A4):
XN
/N-p
XZ Ri
R2
(A4)
wherein R1 and R2 are alkyl which may be substituted
or unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; R1 and R2 may be the
same or different; X1 and X2 are a substituent containing
at least one of an aliphatic group, an aromatic group,
hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro, nitroso, halogen or hydrogen, provided that
when X1 and X2 contain an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
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phosphorous, boron and halogen atoms; when X1 and X2
contain an aromatic group, the aromatic group may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; when X1 and X2 contain hydroxy, the
hydroxy may form a salt with a metal atom; when X1 and X2
contain alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro or nitroso, these substituents may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; X1 and X2 may be the same or different;
and Xl and X2 may form a ring.
In the above active material for a secondary battery,
both of the alkyls R1 and R2 may be methyl.
In the above active material for a secondary battery,
the radical compound may be the nitroxyl radical compound
in which a nitrogen atom in the nitroxyl radical is bound
to two carbon atoms bound to at least two alkyls,
represented by general formula (A5):
27
CA 02617291 2008-01-24
R1
X1,, R2
0
XZ'~ R3
R4
(A5)
wherein R1 to R4 are alkyl which may be substituted
or unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; R1 to R4 may be the
same or different; X1 and X2 are a substituent containing
at least one of an aliphatic group, an aromatic group,
hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
amino, nitro, nitroso, halogen or hydrogen, provided that
when X1 and X2 contain an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X1 and X2
contain an aromatic group, the aromatic group may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; when X1 and X2 contain hydroxy, the
hydroxy may form a salt with a metal atom; when X1 and X2
contain alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano,
28
CA 02617291 2008-01-24
amino, nitro or nitroso, these substituents may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; Xi, and X2 may be the same or different;
and Xl and X2 may form a ring.
In the above active material for a secondary battery,
all of the alkyls Rl to R4 may be methyl.
In the above active material for a secondary battery,
the radical compound may be the nitroxyl radical compound
in which a nitrogen atom in the nitroxyl radical is bound
to at least one aryl, represented by general formula (A6):
x
~
N 0
Ar/
(Afi)
wherein Ar is aryl which may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; X is a substituent containing at least one of an
aliphatic group, an aromatic group, hydroxy, alkoxy,
aldehyde, carboxyl, alkoxycarbonyl, cyano, amino, nitro,
nitroso, halogen or hydrogen, provided that when X contains
29
CA 02617291 2008-01-24
an aliphatic group, the aliphatic group may be saturated or
unsaturated, substituted or unsubstituted, and straight,
cyclic or branched, and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains an aromatic group, the aromatic
group may be substituted or unsubstituted and may contain
at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains
hydroxy, the hydroxy may form a salt with a metal atom;
when X contains alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro or nitroso, the substituent may be
substituted or unsubstituted and may contain at least one
of oxygen, nitrogen, sulfur, silicon, phosphorous, boron
and halogen atoms; and X may form a ring.
In the above active material for a secondary battery,
the aryl may be substituted or unsubstituted phenyl.
In the above active material for a secondary battery,
the radical compound may form the substituted or
unsubstituted heterocycle represented by general formula
(A7):
CA 02617291 2008-01-24
t~ ~ n N_..._ 0
(A7)
wherein X is carbon, oxygen, nitrogen, sulfur,
silicon, phosphorous or boron atom, provided that X may be
the same or different; X may be bound via saturated or
unsaturated bonds; X may form a bond with any substituent;
this compound may be a polymer which may be straight,
cyclic or branched; and n is an integer of 2 to 10 both
inclusive.
In the above active material for a secondary battery,
the nitroxyl radical compound may be that having a
piperidinoxyl ring structure represented by general formula
(A8):
R1
R2
X Q
R3
R4
(A8)
31
CA 02617291 2008-01-24
where R1 to R4 are alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may,
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
In the above active material for a secondary battery,
the nitroxyl radical compound may be that having a
pyrrolidinoxyl ring structure represented by general
formula ( A9 ) :
32
CA 02617291 2008-01-24
R1
X R2
N Q=
R3
R4
(A9)
where R1 to R4 are alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
33
CA 02617291 2008-01-24
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
In the above active material for a secondary battery,
the nitroxyl radical compound may be that having a
pyrrolinoxyl ring structure represented by general formula
(A10):
1
x R2
N-0
R3
R4
(A 1 0)
where R1 to R4 are alkyl which may be substituted or
unsubstituted, straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; X is a substituent
containing at least one of an aliphatic group, an aromatic
group, hydroxy, alkoxy, aldehyde, carboxyl, alkoxycarbonyl,
cyano, amino, nitro, nitroso, halogen or hydrogen, provided
that when X contains an aliphatic group, the aliphatic
34
CA 02617291 2008-01-24
group may be saturated or unsaturated, substituted or
unsubstituted, and straight, cyclic or branched, and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; when X contains an
aromatic group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X contains hydroxy, the hydroxy may form a salt
with a metal atom; when X contains alkoxy, aldehyde,
carboxyl, alkoxycarbonyl, cyano, amino, nitro or nitroso,
the substituent may be substituted or unsubstituted and may
contain at least one of oxygen, nitrogen, sulfur, silicon,
phosphorous, boron and halogen atoms; and X may form a ring.
In the above active material for a secondary battery,
the radical compound may be a compound forming a
nitronylnitroxide structure, represented by general formula
(All):
X1\
(+O N- O O
X3
/N-0
x2
(A1 1)
where X1 to X3 are a substituent containing at least
CA 02617291 2008-01-24
one of an aliphatic group, an aromatic group, hydroxy,
alkoxy, aldehyde, carboxyl, alkoxycarbonyl, cyano, amino,
nitro, nitroso, halogen or hydrogen, provided that when X1
to X3 contain an aliphatic group, the aliphatic group may
be saturated or unsaturated, substituted or unsubstituted,
and straight, cyclic or branched, and may contain at least
one of oxygen, nitrogen, sulfur, silicon, phosphorous,
boron and halogen atoms; when X1 to X3 contain an aromatic
group, the aromatic group may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; when X1 to X3 contain hydroxy, the hydroxy may form
a salt with a metal atom; when X1 to X3 contain alkoxy,
aldehyde, carboxyl, alkoxycarbonyl, cyano, amino, nitro or
nitroso, these substituents may be substituted or
unsubstituted and may contain at least one of oxygen,
nitrogen, sulfur, silicon, phosphorous, boron and halogen
atoms; Xl to X3 may be the same or different; and Xl to X3
may form a ring.
In the above active material for a secondary battery,
the nitroxyl radical compound may be a polymer compound.
In the above active material for a secondary battery,
the polymer compound may be that having a polyacetylene
chain as a main chain.
In the above active material for a secondary battery,
the polymer compound may be that having a polyphenylene-
36
CA 02617291 2008-01-24
vinylene chain as a main chain.
In the above active material for a secondary battery-,
the radical compound may comprise an oxy radical compound.
In the above active material for a secondary battery,
the oxy radical compound may be an aryloxy radical compound.
In the above active material for a secondary battery,
the aryloxy radical compound may comprise arylpolyoxy
radical group.
In the above active material for a secondary battery,
the aryloxy radical compound may comprise a tert-butyl
group.
In the above active material for a secondary battery,
the aryloxy radical compound may comprise a di-tert-
butylphenoxy radical group.
In the above active material for a secondary battery,
the oxy radical compound may be that containing a semi-
quinone.
In the above active material for a secondary battery,
the oxy radical compound may be a compound which is poorly
soluble in a basic solvent.
In the above active material for a secondary battery,
the oxy radical compound may be a polymer radical compound.
In the above active material for a secondary battery,
the polymer radical compound may be that having a
polyolefin structure.
In the above active material for a secondary battery,
37
CA 02617291 2008-01-24
the polymer radical compound may be that having a
polyacetylene structure.
In the above active material for a secondary battery,
the polymer radical compound may be that having a
polyphenylene structure.
In the above active material for a secondary battery,
the polymer radical compound may be that having a five-
membered aromatic heterocyclic structure.
In the above active material for a secondary battery,
the polymer radical compound may be that having a three-
dimensional network structure.
In the above secondary battery, the radical compound
may comprise a compound having a radical on a nitrogen atom.
In the above active material for a secondary battery,
the radical compound may comprise a compound having a
radical on a nitrogen atom in an oxidized form.
In the above active material for a secondary battery,
the radical compound may comprise a compound having a
radical on a nitrogen atom in a reduced form.
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be
that having a radical on a trivalent pherdazyl group
represented by chemical formula (Cl) or a tetravalent
pherdazyl group represented by chemical formula C(2):
38
CA 02617291 2008-01-24
_. /
N-N
(C 1)
N-N
~
/
N--N
(1 (C 2)
WN
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be
that having a triphenylpherdazyl group represented by
chemical formula (C3) or (C4);
N--N
(C3)
NN
39
CA 02617291 2008-01-24
i~
(C4)
btV-
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be
that having a radical on a trivalent hydrazyl group
represented by chemical formula(C5):
' =
N-N-- (C 5)
/
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be
that having a radical on a trivalent hydrazyl group
represented by chemical formula (C6):
CA 02617291 2008-01-24
R1 R3
~ =
N-- R4 (C 6)
R I
Z
R5
where R1 to R5 independently represent hydrogen,
substituted or unsubstituted aliphatic or aromatic
hydrocarbon, halogen, hydroxy, nitro, nitroso, cyano,
alkoxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, acyl or
carboxy.
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be
diphenylpicrylhydrazyl.
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be
that having an aminotriazine structure represented by
general formula (C7):
Rs
N (C1)
N N
41
CA 02617291 2008-01-24
where R6 represents hydrogen, substituted or
unsubstituted aliphatic or aromatic hydrocarbon, halogen,
hydroxy, nitro, nitroso, cyano, alkoxy, aryloxy,
alkoxycarbonyl, aryloxycarbonyl, acyl, carboxy or oxo
radical.
In the above active material for a secondary battery,
the compound having a radical on a nitrogen atom may be a
polymer compound.
In the above active material for a secondary battery,
the compound having an aminotriazine structure may be a
polymer compound having the aminotriazine structure
represented by general formula (C7) as a repeating unit.
This invention provides a secondary battery on the
basis of a novel mechanism that a radical compound is used
as an electrode active material. When the radical compound
consists of lighter materials such as carbon, hydrogen and
oxygen, it may be expected to provide a secondary battery
with a high energy density per a weight. Furthermore, since
only a radical site contributes a reaction in a secondary
battery, this invention may provide a stable secondary
battery whose cycle properties are independent of diffusion
of the active material. In addition, since a reactive
unpaired electron is localized on a radical atom in a
radical compound, a concentration of the reactive site may
be increased to provide a large-capacity secondary battery.
This invention may be suitably applied to a secondary
42
CA 02617291 2008-01-24
battery or active material for a secondary battery which
performs charge and discharge.
An electrode active material as used herein refers to
a material directly contributing to an electrode reaction
such as charge and discharge reactions, and plays a main
role in a secondary battery system. An active material in
this invention may be used as either a positive electrode
or negative electrode active material, but it may be more
preferably used as a positive electrode active material
because it is characterized by a light weight and has a
good energy density in comparison with a metal oxide system.
In the light of stability, it is preferable that
among electrode reactions in a positive electrode, an
electrode reaction during discharge is that in which a
radical compound is a reactant. Furthermore, when the
reaction is that in which a reaction product may form a
bond with an electrolyte cation, much more improvement in
stability may be expected. Any type of electrolyte cations
may be used, and in particular, a lithium ion is preferable=
in the light of a capacity.
As used herein, a reactant refers to a substance
which is subject to a chemical reaction and stably exists
for a long time, while a product refers to a substance
formed as a result of a chemical reaction which stable
exists for a long time. In this invention, a reactant or
product is a radical compound. This invention, therefore,
43
CA 02617291 2008-01-24
570-101
does not encom~ass a system in which a radical is formed
for a quite short time as a reaction intermediate in the
course of an electrode reaction.
According to a statistical mechanical theory, any
chemical substance would contain radical-form species at
room temperature. In this invention, it is, however,
important that radicals exist to an extent where they may
function as an active material in a secondary battery.Tor
example, JP Patent .2,715,778 has indicated organic
compounds such as polyaniline, polypyrrole, polythiophene
and a disulfide as an electrode active material, whose
radical concentration is about 1018 spin/g..
In contrast, a concentration of a radical compound in
this invention is preferably kept to 1019 spin/g or more,
more preferably 1021 spin/g or more, in the light of a
capacity in a secondary battery.
In general, a radical concentration may be expressed
as a spin concentration. Here the spin concentration means
the number of unpaired electrons (radicals) per a unit
weight, which is determined by, for example, the following
procedure from an absorption area intensity in an electron
spin resonance spectrum (hereinafter, referred to as an
"ESR" spectrum). First, a sample to be measured by ESR
spectroscopy is pulverized by grinding it in, for example,
a mortar, whereby the sample may be ground to a particle
size in which skin effect, i.e., a phenomenon that
44
CA 02617291 2008-01-24
microwave does not penetrate a sample, can be ignored. A
given amount of the pulverized sample is filled in a quartz
glass capillary with an inner diameter of 2 mm or less,
preferably 1 to 0.5 mm, vacuumed to 10-5 mmHg or less,
sealed and subject to ESR spectroscopy. ESR spectroscopy
may be conducted using an apparatus such as Model JEOL-JES-
FR30 ESR spectrometer. A spin concentration may be
determined by integrating twice an ESR signal obtained and
comparing it to a calibration curve. There are no
restrictions to a spectrometer or measuring conditions as
long as a spin concentration can be accurately determined.
As described above, a spin concentration for a radical
compound may be evaluated by, for example, electron spin
resonance spectroscopy. A charge state in a radical
compound is preferably neutral in the light of easy
charge/discharge reactions. For stability of a secondary
battery, a radical compound is desirably stable. A stable
radical as used herein refers to a compound whose radical
form has a long life. A longer radical life is better, but
it depends on various factors such as reactivity of the
radical itself and ambient conditions such as a solvent.
A radical is a chemical species with an unpaired
electron and a compound having the chemical species is a
radical compound. A radical is generally highly reactive
and is frequently an unstable species generated as an
intermediate in a variety of reactions. Such an unstable
CA 02617291 2008-01-24
radical forms a bond with a surrounding substance present
in a reaction system and disappears in a certain life.
Some of stable radicals, however, do not form a bond
with a surrounding substance and stably exist for a
relatively longer period. These compounds stabilize a
radical by steric hindrance with an organic protective
group or delocalization of a6-electron. An electrode
active material of this invention utilizes such a compound
generally exhibiting a spin concentration of 1019 to 1023
spins/g determined by electron spin resonance spectroscopy
for a long period, e.g., 1 sec or longer.
In particular, a stable radical compound herein is a
compound in which a spin concentration of 1021 spins/g or
more in an equilibrium state is kept for 1 sec or longer.
A radical compound herein is a compound having an
unpaired electron as a uncombined hand and thus does not
encompass a transition metal compound having a stable
unpaired electron in its inner shell.
Generally, an electrode active material in a
secondary battery may take either an oxidized or reduced
form depending on its starting state and an electrode
reaction, and this invention is wherein the active material
comprises a radical compound either in a starting state or
in an oxidized or reduced state. A charge/discharge
mechanism
is not clearly understood, but may be assumed that a
46
CA 02617291 2008-01-24
radical group in an active material would be reversibly
changed into a radical or ion state by an electrode
reaction for accumulating charge. Furthermore, this
invention is wherein an oxy radical compound directly
contributes to an electrode reaction in a positive
electrode or negative electrode, and therefore, an
electrode used as an active material is not limited to one
of the positive electrode and the negative electrode. A
radical compound is, however, preferably used as an
electrode active material in a positive electrode in the
light of an energy density. For stability, an electrode
reaction during discharge among electrode reactions in a
positive electrode is that in which a radical compound is a
reactant. Furthermore, when a product in this reaction
forms a bond with a cation of an electrolyte salt, further
improvement in stability may be expected. There are herein
no restrictions to the electrolyte cation, but a lithium
ion is preferable in the light of a capacity.
Examples of a radical compound in this invention
include a compound having a nitroxyl radical group, an oxy
radical compound, a compound having a sulfur radical, a
compound having a radical on its nitrogen atom and a
compound having a carbon radical.
Nitroxyl radical compound
A nitroxyl radical compound particularly exhibits
good radical stability. A nitroxyl radical compound refers
47
CA 02617291 2008-01-24
to a compound having a nitroxyl radical group represented
by formula (Al).
N 0=
~
(A1)
A nitroxyl radical group is a substituent in which an
oxygen atom forming a nitroxide group having a bond between
the oxygen and nitrogen has an unpaired electron. Generally,
a radical compound is a highly reactive chemical species.
It is, therefore, frequently unstable and interacts with a
surrounding material to disappear within a certain life. A
nitroxyl radical compound is, however, wherein the unpaired
electron on the oxygen atom is stabilized by an
electroattracting group on the nitrogen atom.
Oxy radical compound
An oxy radical compound is a compound having a
substituent comprising an oxygen atom having an unpaired
electron. Generally, a oxy radical is a highly reactive
chemical species. It is, therefore, frequently unstable and
interacts with a surrounding material to disappear within a
certain life, but may be stable depending on resonance
effect, steric hindrance and solvation conditions. Some of
these stable oxy radical compounds may exhibit a spin
48
CA 02617291 2008-01-24
concentration of 1019 to 1023 spins/g determined by electron
spin resonance spectroscopy for a long time.
When an oxy radical compound consists of lighter
materials such as carbon, hydrogen and oxygen, a secondary
battery with an energy density per a unit weight may be
provided. Furthermore, since only an oxy radical site
contributes to a reaction in a secondary battery according
to this invention, the battery may be stable without
dependency of cycle properties on diffusion of an active
material. In addition, an unpaired electron which reacting
as an electrode active material is localized on a radical
atom in an oxy radical compound, so that a concentration of
the oxy radical as a reaction site can be increased to
provide a large-capacity secondary battery with a higher
energy density.
Compound having a radical on a nitrogen atom
A compound having a radical on a nitrogen atom is a
compound having a substituent comprising a nitrogen atom
having an unpaired electron. Generally, a radical is a
highly reactive chemical species. It is, therefore,
frequently unstable and interacts with a surrounding
material to disappear within a certain life, but may be
stable depending on resonance effect, steric hindrance and
solvation conditions. Some of these stable compounds having
a radical on a nitrogen atom may exhibit a spin
concentration of 1019 to 1023 spins/g determined by electron
49
CA 02617291 2008-01-24
spin resonance spectroscopy for a long time.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.1 is a plan view illustrating an embodiment of a
secondary battery configuration according to this invention.
Fig.2 is a cross section illustrating an embodiment
of a secondary battery configuration according to this
invention.
Fig.3 shows discharge curves for a secondary battery
determined in Examples 1 to 3 according to this invention
and Comparative Example 1.
Fig.4 shows a charge/discharge curve determined in
Example 1 according to this invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Materials constituting an electrode
A secondary battery according to this invention may
(i) use a material comprising a radical compound as
an active material, or
(ii) utilize an electrode reaction in which a radical
compound is a reactant or product.
The electrode reaction in the above (ii) may be a
discharge reaction in which a radical compound is a
reactant or product. A discharge reaction in which a
radical compound is a reactant may be, for example, that
forming a bond between a radical compound and an
electrolyte cation. A discharge reaction in which a radical
compound is a product may be, for example, that cleaving a
CA 02617291 2008-01-24
bond between a radical compound and an electrolyte cation.
Examples of a radical compound used in this invention
include the nitroxyl radical compounds represented by
chemical formulas 1 to 3; the polymer nitroxyl radical
compounds represented by chemical formulas 4 to 6; the
phenoxyl radical compounds represented by chemical formulas
7 and 8; the polymer phenoxyl radical compounds represented
by chemical formulas 9 and 10; the hydrazyl radical
compounds represented by chemical formulas 11 to 13; the
hydrazyl radical compounds represented by chemical formulas
14 and 15; carbon radical compounds; sulfur radical
compounds; and boron radical compounds. It may be a low-
molecular weight or polymer compound. It may be a polymer
compound in which one of the above compound is present.
Furthermore, two or more radical compounds may be mixed. As
shown in chemical formula 16, a substance forming a radical
compound by releasing lithium by charging may be used.
A polymer compound as used herein is an aggregate of
polymers having a large molecular weight, exhibiting
insolubility in a variety of solvents due to its
intermolecular interaction compared to a low molecular
weight compound. Therefore, when a secondary battery is
formed using a polymer radical compound, elution from an
electrode may be minimized to provide good stability. It is
necessary in this invention that a radical compound as an
active material is retained on the electrode during
51
CA 02617291 2008-01-24
charging/discharging. The radical compound is, therefore,
preferably insoluble in a basic solvent constituting an
electrolyte solution. However, when forming a large-
capacity secondary battery, the amount of an electrolyte or
electrolyte solution to an active material is so small that
an insoluble radical compound with a solubility of about 1
g or less (the amount (grams) of a solute to 100 g of a
solvent) may be stably retained on the electrode.
52
CA 02617291 2008-01-24
formula 1 formula 2 formula 3- formula 4
00
40 n
7(N
- cN
\
b N
0
.
0.4 'N
formula 5 formula 6 formula 7
n n
~ 0 -'
0 H 0
-
N
~
*
.
formula 8 formula 9 formula 1Q
= n Xn
= o
0 0
formu l a ii formu l a'12
QO2N
N -N NO 2 N-N
00 0 2N N -N
53
CA 02617291 2008-01-24
formula13 formulal4
n
a =
N -N -CN -N -N
N!=N
4 Noe
formulal5 formulal6
In
CL
i
=N
i
N
In this invention, a radical compound as an active
material is used in both or one of a positive electrode and
a negative electrode layers. When using it in one of the
layers, a well known material as an active material in a
secondary battery may be used in the other electrode layer.
Examples of such a conventional material include, metal
54
CA 02617291 2008-01-24
oxide particles, disulfide compounds and conductive
polymers as a positive electrode layer when using a radical
compound in a negative electrode layer. Herein, examples of
a metal oxide include lithium manganate or lithium
manganate with a spinel structure such as LiMnO2 and
Li,sMn204 ( 0<x<2 ), Mn02, LiCo02 , LiNiO2 and LiXV2O5 ( 0<x<2 ).
Examples of a conductive polymer include polyacetylene,
polyphenylene, polyaniline and polypyrrole.
In this invention, these materials for a positive
electrode layer may be used alone or in combination of two
or more. A radical compound may be mixed with a known
active material to be used as a complex active material.
On the other hand, when using a radical compound in a
positive electrode, examples of a material for a negative
electrode layer include carbon materials such as graphite
and amorphous carbon, lithium metal or a lithium alloy,
lithium-ion occluding carbon and conductive polymers. These
materials may take an appropriate form such as film, bulk,
granulated powder, fiber and flake.
In this invention, a conductive auxiliary material or
ion-conductive auxiliary material may be added for reducing
an impedance during forming an electrode layer comprising a
radical compound. Examples of such a material include
carbonaceous particles such as graphite, carbon black and
acetylene black and conductive polymers such as polyaniline,
polypyrrole, polythiophene, polyacetylene and polyacene as
CA 02617291 2008-01-24
a conductive auxiliary material as well as a gel
electrolyte and a solid electrolyte as an ion-conductive
auxiliary material.
In this invention, a binder may be used for
reinforcing binding between components. Examples of a
binder include polyvinylidene fluoride, a copolymer of
vinylidene fluoride and hexafluoropropylene, a copolymer of
vinylidene fluoride and tetrafluoroethylene,
polytetrafluoroethylene, a copolymer rubber of styrene and
butadiene, and resin binders such as polypropylene,
polyethylene and polyimide.
In this invention, a catalyst may be used for
accelerating an electrode reaction. Examples of a catalyst
include conductive polymers such as polyaniline,
polypyrrole, polythiophene, polyacetylene and polyacene;
basic compounds such as pyridine derivatives, pyrrolidone
derivatives, benzimidazole derivatives, benzothiazole
derivatives and acridine derivatives; and metal-ion
complexes.
This invention is characterized in that an active
material in at least one of a positive electrode and a
negative electrode comprises a radical compound, but there
are no restrictions to its amount. However, since a
capacity as a secondary battery depends on the amount of
the radical compound contained, the content is desirably 1
wt% or more for achieving adequate effects of this
56
CA 02617291 2008-01-24
.570-101
invention. The content lower than the limit may lead to
inadequate effects of this invention of a higher energy
density and a larger capacity.
Structure of a second battery
A secondary battery according to this invention
has a configuration, for example, as shown in Fig. 1, where
a negative electrode layer 1 and a positive electrode
layer 2 are piled via a separator 5 containing an
electrolyte and are contained in a space formed by an
outside layer film 8. Terminals 6 and 7 are attached to the
positive and negative electrode layers, respectively. In
this invention, an active material used in the negative
electrode layer 1 or the positive electrode layer 2 is a
radical compound.
Fig. 2 is a cross section of a laminated secondary
battery, where a positive electrode collector 4, a positive
electrode layer 2, a separator 5 containing an electrolyte,
a negative electrode layer 1 and a negative electrode
collector 3 are piled in sequence and are contained in a
space formed by a pair of outside layer films 8. In this
invention, a positive electrode and a negative electrode
layers may be piled as appropriate; for example, the
secondary battery may be a multi-layer laminate, a
combination of collectors with layers on both sides and a
rolled laminate.
The negative electrode collector 3 and the
positive electrode collector 4 may be a metal foil or metal
plate made of, for example, nickel, aluminum, copper, gold,
silver, an aluminum alloy and stainless steel; a mesh
electrode; and a carbon electrode. The collector may be
active as a catalyst or an active material may be chemical
57
CA 02617291 2008-01-24
bound to a collector. A separator made of a porous film or
a nonwoven fabric may be used for preventing the above
positive electrode from being in contact with the negative
electrode.
An electrolyte contained in the separator 5 transfers
charged carriers between the electrodes, i.e., the negative
electrode 1 and the positive electrode 2, and generally
exhibits an electrolyte-ion conductivity of 10-5 to 10-1
S/cm at room temperature. An electrolyte used in this
invention may be an electrolyte solution prepared by, for
example, dissolving an electrolyte salt in a solvent.
Examples of such a solvent include organic solvents such as
ethylene carbonate, propylene carbonate, dimethyl carbonate,
diethyl carbonate, methyl ethyl carbonate, y-butyrolactone,
tetrahydrofurane, dioxolane, sulforane, dimethylformamide,
dimethylacetamide and N-methyl-2-pyrrolidone. In this
invention, these solvents may be used alone or in
combination of two or more. Examples of an electrolyte salt
include LiPF6, LiC1O4, LiBF4, LiCF3SO3, LiN(CF3SO2)2,
LiN ( C2F5S02 ) 2, LiC ( CF3SO2 ) 3 and LiC ( C2F5SOZ ) 3.
An electrolyte may be solid. Examples of a polymer
used in the solid electrolyte include vinylidene fluoride
polymers such as polyvinylidene fluoride, a copolymer of
vinylidene fluoride and hexafluoropropylene, a copolymer of
vinylidene fluoride and ethylene, a copolymer of vinylidene
fluoride and monofluoroethylene, a copolymer of vinylidene
58
CA 02617291 2008-01-24
fluoride and trifluoroethylene, a copolymer of vinylidene
fluoride and tetrafluoroethylene and a terpolymer of
vinylidene fluoride, hexafluoropropylene and
tetrafluoroethylene; acrylonitrile polymers such a
copolymer of acrylonitrile and methyl methacrylate, a
copolymer of acrylonitrile and methyl acrylate, a copolymer
of acrylonitrile and ethyl methacrylate, a copolymer of
acrylonitrile and ethyl acrylate, a copolymer of
acrylonitrile and methacrylic acid, a copolymer of
acrylonitrile and acrylic acid and a copolymer of
acrylonitrile and vinyl acetate; polyethylene oxide; a
copolymer of ethylene oxide and propylene oxide; and
polymers of these acrylates or methacrylates. The polymer
may contain an electrolyte solution to form a gel or the
polymer may be used alone.
A secondary battery in this invention may have a
conventional configuration, where, for example, an
electrode laminate or rolled laminate is sealed in, for
example, a metal case, a resin case or a laminate film made,
of a metal foil such as aluminum foil and a synthetic resin
film. It may take a shape of, but not limited to,
cylindrical, prismatic, coin or sheet.
A secondary battery according to this invention may
be prepared by a conventional process. For example, a
slurry of an active material in a solvent is applied on an
electrode laminate and the product is piled with a counter
59
CA 02617291 2008-01-24
570-101
electrode via a separator. Alternatively, the laminate is
rolled and placed in a case, which is then filled with an
electrolyte solution. A secondary battery may be prepared
using a radical compound itself or using a compound which
cari be converted into a radical compound by a redox
reaction. Examples of a compound which can be converted
into a radical compound by a redox reaction include a
lithium or sodium salt of an anion generated by reduction
of a radical compound. In this invention, a secondary
battery may be prepared using a compound which can be
converted into a radical compound as a result of a redox
reaction.
Nitroxyl radical compound
A nitroxyl radical compound in this invention has a
nitroxyl radical group in a molecular structure. Chemical
formulas A12 to A48 shows specific examples of a nitroxyl
radical compound.
A compound in which a bulky alkyl group is attached
to a nitrogen atom forming a nitroxyl radical group is
expected to be highly stable because of its steric
hindrance. Such an alkyl is preferably tert-butyl. Chemical
formulas (A12) to (A19) are examples of a compound in which
a tert-butyl group is attached to a nitrogen atom forming a
nitroxyl radical group.
In the light of stability in a radical, it is
preferable that a carbon atom to which at least two alkyl
CA 02617291 2008-01-24
groups are attached is bound to a nitrogen atom forming a
nitroxyl radical group. In particular, when the nitrogen
atom is bound to two carbon atoms to each of which at least
two alkyl groups are attached, it may be expected that a
more stable radical compound is provided. The alkyl group
herein is preferably methyl. Chemical formulas (A12) to
(A20) and (A24) to (A48) show examples of a compound in
which a carbon atom to which two methyl groups are attached
is bound to a nitrogen atom forming a nitroxyl radical
group.
A compound in which an aryl group is attached to a
nitrogen atom forming a nitroxyl radical group is expected
to be more stable because of electron delocalization. The
aromatic group herein is preferably a substituted or
unsubstituted phenyl group in the light of stability.
Chemical formulas (A13) to (A19) and (A21) and (A22) show
examples of a compound in which an aryl group is attached
to a nitrogen atom forming a nitroxyl radical group.
When a nitrogen atom forming a nitroxyl radical group,
is one member of a heterocycle, it may be expected that
stability of a radical is improved because it may inhibit
an intramolecular reaction of the nitroxyl radical group.
The heterocycle herein is preferably a piperidinoxy,
pyrrolidinoxy or pyrrolinoxy ring in the light of stability.
Chemical formulas (A23) to (A48) show examples of a
compound in which a nitrogen atom forming a nitroxyl
61
CA 02617291 2008-01-24
radical group is one member of a heterocycle; specifically,
chemical formulas (A26) to (A30) for a piperidinoxy ring, -
chemical formulas (A31) to (A36) for a piperidinoxy ring
and chemical formulas (A37) to (A41) for a piperidinoxy
ring.
When a nitroxyl radical group forms a
nitroxylnitroxide structure, it may be expected that a
radical is more stable because of electron delocalization.
Chemical formulas (A43) to (A48) show examples of a
compound having a nitroxylnitroxide structure.
A compound in which a nitroxy radical compound is a
polymer compound is preferable because it is resistant to
dissolving by an electrolyte solution to give good
stability without deterioration for a long time. Such a
polymer compound may be straight, cyclic or branched.
Furthermore, a compound having a polyacetylene or
polyphenylene vinylene chain as a main chain may be highly
stable because of electronic delocalization.
A nitroxyl radical compound as an active material in
a secondary battery according to this invention may be a
solid or a solution, without any restriction in terms of
operation. It is, however, preferably insoluble in a basic
solvent in the light of a rate and an efficiency in
charge/discharge. There are no restrictions to a molecular
weight of a nitroxyl radical compound in this invention,
and a variety of molecular weight may be thus acceptable
62
CA 02617291 2008-01-24
from a compound with a low molecular weight to a polymer
compound. However, a polymer is preferable in the light of
stability of its charged or discharged state, particularly
a polymer radical having a polyacetylene or polyphenylene
structure. Examples of a compound in which a nitroxyl
radical compound forms a polymer compound are shown in
chemical formulas (A16) to (A20), (A22), (A25), (A29),
(A30), (A42) and (A46) to (A48). Specifically, chemical
formulas (A16), (A17), (A22), (A29), (A30) and (A46) show
examples of a compound having a polyacetylene chain as a
main chain while chemical formulas (A18), (A19) and (A47)
show examples of a compound having a polyphenylene vinylene
chain as a main chain.
63
CA 02617291 2008-01-24
(A 1 2) ~ (A 1 8) oN n
0 104 (A13) N
,
YNJO O.
p (A 1 9) 0 t' (A 1 4) N-O. n
Y NO N
O O (A2 0)
(A15)
O
0 0
oN N No (A21)
6 ~ 0
0 ~ o.
N-O-
(A1 6)
,~ o
n
o (A2 2)
1-7:zt n
.O, N/, 0
(A 1 7) .O, N
n a
OCH3
=O' N
(A 2 3) -
0
64
CA 02617291 2008-01-24
(A2 4) O (A2 9)
NH
N
~
N
(A2 5)
n
t
o N
O
N ~ N-O= (A 3 0) 4-~ ~ n
OH
(A2 6) N
7(
O
0
(A31) OH
(A27) 0
O
.
N
p (A3 2) CN
(A2 8) S S ry
, o
N S S
(A3 3) NH2
N
ry
O
(A3 4) 0 O
N
O
CA 02617291 2008-01-24
(A3 5) S (A4 2) ~~N~n
N 1'
~D S s
0
N
0 0
.
(A36) .~ _~' ' \ (A43) Oa
N N-N N N~N
O Q a N
4
(A3 7) OH
- (A44) Oe
,
N CN}a
O NN
. ~
,
O
(A38) CN (A4 5) 00
I
N
N C
N
9
(A39) NH2
(A4 6)
n
N
6 0
(A40) 0 o Oe o~ -N N-Oo
(A47)
n
(A41) 0 O
N
- N N.O
D N
.~~
O
66
CA 02617291 2008-01-24
(A48)
~Op n
0
e~-.N~ _p.
Oxy radical compound
An oxy radical compound used in this invention has an
oxy radical group in its molecular structure. It preferably
has an aryloxy radical group or semiquinone in the light of
stability of a radical state.
Examples of an oxy radical compound are shown below.
67
CA 02617291 2008-01-24
B1
00
ao
0
B2
a O on
B3
R
.0 0'P
B 4 R R
O p
R
c Q.
H
68
CA 02617291 2008-01-24
i
o N O 0=
B8
Q
0 ' o 0 0 '
o Q
B9
o Q Q n
9
69
CA 02617291 2008-01-24
n
B1~
~
o-
B11 n
o=
B12
nn
0
o=
CA 02617291 2008-01-24
B13
0
0
o -
B14
0
. a , .
.~ o
71
CA 02617291 2008-01-24
B15
0
a a ~
B16
n
O
B17
72
CA 02617291 2008-01-24
18
B 1 9
n
0
0
.
73
CA 02617291 2008-01-24
B20
a No ~
H n
p.
S
n
BZ1
a
74
CA 02617291 2008-01-24
B 2 2 s
1 I n
0
0
a
B23 s
1 / s n
~
0
A compound having an aryloxy radical indicates an
aromatic compound such as benzene, naphthalene and
thiophene having an oxy radical group, while a compound
having semiquinone indicates a structure formed by
incomplete combustion of a benzenoid and a quinoid
compounds. A compound having an aryloxy radical compound is
CA 02617291 2008-01-24
preferably that having an arylpolyoxy radical group or a
tertiary butyl group. A compound having a tertiary butyl
group is that having a di-tert-butylphenoxy radical group.
Examples of a compound having an aryloxy radical group are
those shown in chemical formula Bl to 3 and their
derivatives. Examples of a compound having an arylpolyoxy
radical group are that shown in chemical formula B4 and its
derivatives. Examples of an aryloxy radical compound having
a di-tert-butyl group are those shown in chemical formulas
B5 to 8 and their derivatives. Examples of a semiquinone
are that shown in chemical formula B9 and its derivatives.
An oxy radical compound as an active material in a
secondary battery according to this invention may be a
solid or a solution, without any restriction in terms of
operation. It is, however, preferably insoluble in a basic
solvent in the light of a rate and an efficiency in
charge/discharge. There are no restrictions to a molecular
weight of an oxy radical compound in this invention, and a
variety of molecular weight may be thus acceptable from a
compound with a low molecular weight to a polymer compound.
However, a polymer is preferable in the light of stability
of its charged or discharged state, particularly a polymer
radical compound having a polyolefin, polyacetylene,
polyphenylene or five-membered aromatic heterocycle
structure, most preferably a polymer radical compound
having a three-dimensional network structure. Examples of a
76
CA 02617291 2008-01-24
compound having a polyolefin structure are the polymer
compounds shown in chemical formulas B10 to 11 and their
derivatives. Examples of a compound having a polyacetylene
structure are the polymer compounds shown in chemical
formulas B12 to 15 and their derivatives. Examples of a
compound having a polyphenylene structure are the polymer
compounds shown in chemical formulas B16 to 20 and their
derivatives. Examples of a compound having a five-membered
aromatic heterocycle structure are the polymer compounds
shown in chemical formulas B21 to 23 and their derivatives.
Examples of a compound having a three-dimensional network
structure are the compound shown in chemical formula B24
and its derivatives.
Compound having a radical on a nitrogen atom
A compound having a radical on a nitrogen atom used
as an active material in this invention has a radical on a
nitrogen atom in its molecular structure. Examples of the
compound include those having a radical on an amino group
as described in 0. Shimamura et al., "Yuriki Hannou", Tokyo
Kagaku Dojin, pp.24-34 (1964); the compound having a
radical on a pherdazyl group represented by chemical
formula (C8):
77
CA 02617291 2008-01-24
/ NN-
(C CJ)
N-N '
the compound having a radical on a hydrazyl group
represented by chemical formula (C9):
' =
N-N- (c 9)
/
polymer compounds as described in S. Okawara,
"Kobunshi no Kagaku Hannou", Kagaku Dojin, pp. 340-346
(1972).
More specific examples include the lophine derivative
represented by chemical formula (C10); the
tetraphenylpyrrole derivative represented by chemical
formula (C11); the phenothiazine derivative represented by
chemical formula (C12); 2,2-diphenyl-l-picrylhydrazyl
represented by chemical formula (C13); the 1,1,5,5-
tetraphenyl-1,2,4,5-tetraaza-2-pentene derivative
represented by chemical formula (C14); 1,3,5-
triphenylpheldazyl represented by chemical formula (C15);
the compounds having a triphenylpheldazyl group represented
by chemical formulas (C16) and (C17); the polymer compounds
78
CA 02617291 2008-01-24
having a triphenylpheldazyl group represented by chemical
formulas (C18) to (C25); and the polymer compounds having
an aminotriazine structure represented by chemical formulas
(C26) to (C28).
~1] = (C 1 0)
~
0 0.
(C 1 1) oo
79
CA 02617291 2008-01-24
N
1OIIjJ (C12)
o NO2
N N02 (C 1 3)
N
0 0
N-N=CH-N o (C 1 4)
(C15)
C
no no
o (C16
)
N
= o .
CA 02617291 2008-01-24
ir
H2 ~~ (C 17)
N
a = _
81
CA 02617291 2008-01-24
o ~N o O N (C 1 8)
n
~o 0
0
(C19)
N= 'N
~
0 0
Z N.~
n
o ,~ o
~ (C24)
= N.NJ
i
82
CA 02617291 2008-01-24
n
0
N (C2 1)
~ ,N
N. N~ o
o
~
N'N
N (c 2 2)
N'
0
n
(a C23)
N
=N ~N
0
83
CA 02617291 2008-01-24
N
0 (C24)
NZ
=N N
a i
s a
0 o
+HW O ~~---~ CFI2~--~ , ~-H-R H C
N n
O a (C25)
0 NH2 (c 2 s)
N N
N~N" 1 n
a
= ,
0 (C27)
N ~a"~
N N N~ N' 1 n
84
CA 02617291 2008-01-24
~ o
~
N N (C28)
O ~ .
=~ 'N~rv'~'N'~N~
~ NO2
N02 (C29)
CT N02
o '
N-
O (C30)
N--
0
0
(C31)
~ N
NvN
0 0
CA 02617291 2008-01-24
0
(C32)
N N X)i
N N n
In the above foumulae, n represents an integer of 1
to 8;
In the above foumula C25, R represents, e.g., an
alkylene or aromatic group;
In this invention, there are no restrictions to a
molecular weight of a compound having a radical on a
nitrogen atom and thus a compound with a low molecular
weight from a polymer compound may be used as necessary. A
polymer compound generally has a lower solubility in an
electrolyte solution compared with'a compound with a low
molecular weight, so that a capacity reduction due to
dissolution in the electrolyte solution is smaller.
Examples of a polymer compound include those having any of
the structures represented by chemical formulas C18 to C28,
C31 and C32, as well as polymer compounds having a
polyolefin, polyacetylene, polyphenylene or five-membered
aromatic heterocycle structure. The polymer compound may
86
CA 02617291 2008-01-24
have a three-dimensional network structure. A compound
having a radical on a nitrogen atom as an active material
in a secondary battery in this invention may be solid or
may be dissolved or dispersed in an electrolyte. When using
as a solid, it may be preferably insoluble or poorly
soluble in an electrolyte solution because capacity
reduction due to dissolution in an electrolyte solution may
be minimized. A compound having a radical on a nitrogen
atom as an active material in a secondary battery in this
invention is generally used alone, or in combination of two
or more or another type of active material.
Examples
This invention will be more specifically described
with reference to Examples.
The compounds used in Examples 1 to 5 are as follows.
87
CA 02617291 2008-01-24
formula 1 formula 2 formula;3. formula 4
00
l~o
N n
N
7(
q '0 ' a N
= d
0'R
formula 5 formula 6 formula 7
n n
O 0 0 c 0=
- N
N
~ N
0
.
formula 8 formula 9 formula;l0
n kn
0=
~
0 0
,
formula 11 formula-12
0 2N
NO -N
2 Q ,
OO2N N-N
b
88
CA 02617291 2008-01-24
formulal3 formulal4
n
R-N=CH -N -N
ri
formulal5 formulal6
Inn
OLi =N
N
Example 1
In a dry box equipped with a gas purifier were mixed
60 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene and 140 mg of an electrolyte solution
which was a 1:1 mixture of ethylene carbonate / propylene
carbonate containing 1 mol/L of LiPF6 electrolyte salt
under an atmosphere of argon gas. To the mixture was added
1130 mg of tetrahydrofuran, and the mixture was dissolved
89
CA 02617291 2008-01-24
to prepare a solution of a gel electrolyte in
tetrahydrofuran.
In a separate glass vessel was placed 30 mg of
2,2,6,6-tetramethylpiperidoxyl radical (TEMPO radical)
having the molecular structure represented by chemical
formula 1, which is a nitroxyl radical compound, as a
radical compound, then 60 mg of graphite powder as a
conductive adjuvant and then 200 mg of the above solution
of a gel electrolyte in tetrahydrofuran as an ion-
conductive adjuvant, and the mixture was blended. To the
mixture was added 1000 mg of tetrahydrofuran and the
mixture was further blended until it became homogeneous to
provide a black slurry. Then, 200 mg of the slurry was
added dropwise on the surface of an aluminum foil (area:
1.5 cmxl.5 cm, thickness: 100Eun) with a lead, and the
slurry was spread using a wire bar such that the overall
surface became even. It was left for 60 min at room
temperature to evaporate the solvent, tetrahydrofuran, and
to form an organic compound layer containing TEMPO radical
on the aluminum foil.
An aliquot of the applied film was taken, ground and
subject to electron spin resonance spectroscopy. A spin
concentration was determined with Model JEOL-JES-FR30 ESR
spectrometer under the conditions of a microwave power of 4
mW , a modulation frequency of 100 kHz and a modulation
width of 79 T in a range of 335.9 mT 5 mT. An absorption
CA 02617291 2008-01-24
area intensity was determined by integrating twice a first
derivation type of ESR spectrum obtained as described above
and compared with an absorption area intensity for a known
sample measured under the same conditions to determine a
spin concentration. As a result, a spin concentration was
1021 spin/g or higher, indicating formation of a radical in
an initial state.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate to a thickness of 1 mm. It was
left for 1 hour for spontaneous evaporation of
tetrahydrofuran to provide a gel electrolyte film with a
thickness of 150p,m on the glass plate.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil on which an organic compound
layer containing TEMPO radical had been formed. On the foil
was then laminated a copper foil having a lithium film with
a lead (thickness: 30pm for the lithium film and 20 m for
the copper foil) . The whole product was sandwiched with
polytetrafluoroethylene sheets with a thickness of 5 mm and
was pressed to provide a secondary battery.
91
CA 02617291 2008-01-24
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
aluminum foil with an organic compound layer containing
TEMPO radical as a positive electrode and the copper foil
with a lithium film as a negative electrode. The results
are illustrated in Fig.3, in which a voltage plateau can be
found at about 2.3 V, indicating that the battery acted as
a secondary battery. A part of the compound layer
containing TEMPO radical was removed from the sample after
discharge and it was subject to electron spin resonance
spectroscopy as described above to give a spin
concentration of 1019 spin/g or less. It indicates that
after discharge, TEMPO radical formed a bond with lithium
ion, leading to absence of effective radicals for a redox
reaction.
Another secondary battery prepared as described above
was evaluated for voltage variation in association with
charge/discharge. The results obtained after 10 cycles of
charge/discharge are illustrated in Fig.4, in which a
plateau is seen in a discharge curve after repeated
charge/discharge, indicating that the battery also acted as
a secondary battery.
Secondary batteries were prepared using the polymer
compounds represented by chemical formulas 2, 3 and 4 to 6
in place of TEMPO radical in Example 1 as a nitroxyl
radical compound. They also acted as a secondary battery as
92
CA 02617291 2008-01-24
described in Example 1.
Comparative Example 1
In a glass vessel in Example 1 were mixed a
conductive adjuvant, an ion-conductive adjuvant, a mixed
solution of ethylene carbonate and propylene carbonate and
tetrahydrofuran to prepare a black slurry as described in
Example 1 except that TEMPO radical was absent. Then, on an
aluminum foil was formed a compound layer without TEMPO
radical as described in Example 1. A part of the layer was
removed and subject to electron spin resonance spectroscopy
as described in Example 1 to give a spin concentration of
1019 spin/g or less, indicating a smaller radical
concentration.
The gel electrolyte film in Example 1 was laminated
on the aluminum foil on which a compound layer without
TEMPO radical had been formed and further a copper foil
having a lithium film in Example 1 was laminated. The whole
product was sandwiched with polytetrafluoroethylene sheets
and was pressed as described in Example 1 to provide a
secondary battery.
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
aluminum foil without a compound layer without TEMPO
radical as a positive electrode and the copper foil with a
lithium film as a negative electrode. The results are
illustrated in Fig.3. The battery did not exhibited
93
CA 02617291 2008-01-24
behavior as a secondary battery. When attempting charge by
applying a constant current of 0.1 mA, a voltage
momentarily exceeded 3.0 V hnd after discharge a plateau
was not observed in a voltage curve. It indicated that the
battery with this configuration did not act as a secondary
battery.
Example 2
In a glass vessel in Example 1 were mixed a
conductive adjuvant, an ion-conductive adjuvant, a mixed
solution of ethylene carbonate and propylene carbonate and
tetrahydrofuran to prepare a black slurry as described in
Example 1 except that TEMPO radical was substituted with
galvinoxyl radical having the molecular structure
represented by chemicalrformula 7, a phenoxyl radical
compound. Then, on an aluminum foil was formed a compound
layer containing galvinoxyl radical as described in Example
1. A part of the layer was removed and subject to electron
spin resonance spectroscopy as described in Example 1 to
give a spin concentration of 1021 spin/g or more,
indicating that a radical was formed in an initial state.
On the aluminum foil having the compound layer
containing galvinoxyl radical were sequentially laminated
the gel electrolyte film in Example 1 and the copper foil
with a lithium film. Then, the whole product was sandwiched
with polytetrafluoroethylene sheets and pressed to prepare
a secondary battery as described in Example 1.
94
CA 02617291 2008-01-24
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
aluminum foil with a compound layer containing galvinoxyl
radical as a positive electrode and the copper foil with a
lithium film as a negative electrode. The results are
illustrated in Fig.3, in which voltage plateaus can be
found at about 2.3 V, 2.0 V and 1.5 V, indicating that the
battery acted as a secondary battery. A part of the
compound layer containing galvinoxyl radical was removed
from the sample after discharge and it was subject to
electron spin resonance spectroscopy as described in
Example 1 to give a spin concentration of 1019 spin/g or
less. It indicates that after discharge, galvinoxyl radical
formed a bond with lithium ion, leading to absence of
effective radicals for a redox reaction.
Voltage variation in association with
charge/discharge was evaluated as described in Example 1.
The results obtained indicated that the battery could be
repeatedly charged/discharged and also acted as a secondary
battery.
Secondary batteries were prepared using the polymer
compounds represented by chemical formulas 8, 9 and 10 in
place of galvinoxyl radical used in Example 2 as a phenoxyl
radical compound. They also acted as a secondary battery as
described in Example 2.
Example 3
CA 02617291 2008-01-24
In a glass vessel in Example 1 were mixed a
conductive adjuvant, an ion-conductive adjuvant, a mixed
solution of ethylene carbonate and propylene carbonate and
tetrahydrofuran to prepare a black slurry as described in
Example 1 except that TEMPO radical was substituted with
2,2-diphenyl-l-picrylhydrazyl radical (DPPH radical) having
the molecular structure represented by chemical,formula 11,
a hydrazyl radical compound.
Then, on an aluminum foil was formed a compound layer
containing DPPH radical as described in Example 1. A part
of the layer was removed and subject to electron spin
resonance spectroscopy as described in Example 1 to give a
spin concentration of 1021 spin/g or more, indicating that
a radical was formed in an initial state.
On the aluminum foil having the compound layer
containing DPPH radical were sequentially laminated the gel
electrolyte film in Example 1 and the copper foil with a
lithium film. Then, the whole product was sandwiched with
polytetrafluoroethylene sheets and pressed to prepare a
secondary battery as described in Example 1.
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
copper foil with a compound layer containing DPPH radical
as a positive electrode and the copper foil with a lithium
film as a negative electrode. The results are illustrated
in Fig.3, in which voltage plateaus can be found at about'
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CA 02617291 2008-01-24
3.1 V and 2.5 V, indicating that the battery acted as a
secondary battery. A part of the compound layer containing
DPPH radical was removed from the sample after discharge
and it was subject to electron spin resonance spectroscopy
as described in Example 1 to give a spin concentration of
1019 spin/g or less. It indicates that after discharge,
DPPH radical formed a bond with lithium ion, leading to
absence of effective radicals for a redox reaction.
Voltage variation in association with
charge/discharge was evaluated as described in Example 1.
The results obtained indicated that the battery could be
repeatedly charged/discharged and also acted as a secondary
battery.
Secondary batteries were prepared using the polymer
compounds represented by chemical formulas 12, 13, 14 and
15 in place of DPPH radical used in Example 3 as a hydrazyl
radical compound. They also acted as a secondary battery as
described in Example 3.
Example 4
In a glass vessel in Example 1 were mixed a
conductive adjuvant, an ion-conductive adjuvant, a mixed
solution of ethylene carbonate and propylene carbonate and
tetrahydrofuran to prepare a black slurry as described in
Example 1 except that TEMPO radical was substituted with
lithium 2,4,6-tri-tert-butylphenoxide having the molecular
structure represented by chemical formula 16. Then, on an
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CA 02617291 2008-01-24
aluminum foil was formed a compound layer containing
lithium 2,4,6-tri-tert-butylphenoxide as described in
Example 1. A part of the layer was removed and subject to
electron spin resonance spectroscopy as described in
Example 1 to give a spin concentration of 1019 spin/g or
less, indicating that there were no radicals in an initial
state.
On the aluminum foil having the compound layer
containing lithium 2,4,6-tri-tert-butylphenoxide were
sequentially laminated the gel electrolyte film in Example
1 and the copper foil with a lithium film. Then, the whole
product was sandwiched with polytetrafluoroethylene sheets
and pressed to prepare a secondary battery as described in
Example 1.
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
copper foil with a compound layer containing lithium 2,4,6-
tri-tert-butylphenoxide as a positive electrode and the
copper foil with a lithium film as a negative electrode.
When the battery voltage became 3.0 V, the voltage was kept
constant. Then charge was terminated when a current value
became 0.01 mA. After a 5 min interval, discharge was re-
started to obtain a discharge curve. In the curve, a
plateau can be found at about 2.3 V, indicating that the
battery acted as a secondary battery. A part of the
compound layer containing lithium 2,4,6-tri-tert-
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butylphenoxide was removed from the sample immediately
after charge and it was subject to electron spin resonance
spectroscopy as described in Example 1 to give a spin
concentration of 1021 spin/g or more. It indicates that
after charge, lithium 2,4,6-tri-tert-butylphenoxide was
converted to 2,4,6-tri-tert-butylphenoxyl radical.
Voltage variation in association with
charge/discharge was evaluated as described in Example 1.
The results obtained indicated that the battery could be
repeatedly charged/discharged and also acted as a secondary
battery.
Example 5
On an aluminum foil was formed a compound layer
containing lithium 2,4,6-tri-tert-butylphenoxide as
described in Example 4. A part of the layer was removed and
subject to electron spin resonance spectroscopy as
described in Example 1 to give a spin concentration of 1019
spin/g or less, indicating that a radical concentration is
low in an initial state.
Then, on a copper foil with a thickness of 20 m was
poured a slurry prepared by mixing polyvinylidene fluoride,
N-methyl-2-pyrrolidone, powdered petroleum coke and
acetylene black in a ratio of 1:30:20:1 by weight and the
slurry was made even with a wire bar. After drying in vacuo
at 100 C for 2 hours, the product was cut in a size of 1.5
cmxl.5 cm to provide an electrode layer containing powdered
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petroleum coke.
On the aluminum foil having the compound layer
containing lithium 2,4,6-tri-tert-butylphenoxide were
sequentially laminated the gel electrolyte film in Example
4 and the electrode layer containing powdered petroleum
coke. Then, the whole product was sandwiched with
polytetrafluoroethylene sheets and pressed to prepare a
secondary battery as described in Example 1.
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
copper foil with a compound layer containing lithium 2,4,6-
tri-tert-butylphenoxide as a positive electrode and the
copper comprising a layer of powdered petroleum coke as a
negative electrode. When the battery voltage became 3.0 V,
the voltage was kept constant. Then charge was terminated
when a current value became 0.01 mA. After a 5 m.in interval,
discharge was started to obtain a discharge curve. In the
curve, a plateau can be found at about 2.0 V, indicating
that the battery acted as a secondary battery. A part of
the compound layer containing lithium 2,4,6-tri-tert-
butylphenoxide was removed from the sample immediately
after charge and it was subject to electron spin resonance
spectroscopy as described in Example 1 to give a spin
concentration of 1021 spin/g or more. It indicates that
after charge, lithium 2,4,6-tri-tert-butylphenoxide was
converted to 2,4,6-tri-tert-butylphenoxyl radical. Voltage
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CA 02617291 2008-01-24
variation in association with charge/discharge was
evaluated as described in Example 1. The results obtained
indicated that the battery could be repeatedly
charged/discharged and also acted as a secondary battery.
Example 6
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of 2,2,6,6-
tetramethylpiperidinoxyl radical (TEMPOa radical) having
the molecular structure represented by chemical formula
(A26) and 60 mg of graphite powder as a conductive adjuvant
under an atmosphere of argon. To the mixture were added 20
mg of a copolymer of vinylidene fluoride and
hexafluoropropylene and 1 g of tetrahydrofuran, and the
mixture was stirred for several minutes until it became
homogeneous to provide a black slurry. A sample of TEMPOa
radical used was subject to electron spin resonance
spectroscopy as described in Example 1 to give a spin
concentration of 1021 spin/g or more.
(A26)
7(N
I
O
Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
cmxl.5 cm, thickness: 100Eun) with a lead, and the slurry
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CA 02617291 2008-01-24
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing TEMPOa radical on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing TEMPOa radical had been formed.
On the foil was then laminated a copper foil having a
lithium film with a lead (thickness: 30 m for the lithium
film and 20 m for the copper foil). The whole product was
sandwiched with polytetrafluoroethylene sheets with a
thickness of 5 mm and was pressed to provide a secondary
battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing TEMPOa radical as a
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positive electrode and the copper foil with a lithium film
as a negative electrode, indicating its action as a
secondary battery. Repeated charge/discharge for the
secondary battery indicated that the battery acted as a
secondary battery capable of charge/discharge for 10 cycles
or more.
Example 7
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of dibutylnitroxyl
radical (DBNO radical) having the molecular structure
represented by chemical formula (A12) and 60 mg of graphite
powder as a conductive adjuvant under an atmosphere of
argon. To the mixture were added 20 mg of a copolymer of-
vinylidene fluoride and hexafluoropropylene and 1 g of
tetrahydrofuran, and the mixture was stirred for several
minutes until it became homogeneous to provide a black
slurry. A sample of DBNO radical used was subject to
electron spin resonance spectroscopy as described in
Example 1 to give a spin concentration of 1021 spin/g or
more.
(A1 2)
Q
.
Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
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CA 02617291 2008-01-24
cmxl.5 cm, thickness: 100E.un) with a lead, and the slurry
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing DBNO radical on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the-mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing DBNO radical had been formed. On
the foil was then laminated a copper foil having a lithium
film with a lead (thickness: 30 m for the lithium film and
20 m for the copper foil). The whole product was sandwiched
with polytetrafluoroethylene sheets with a thickness of 5
mm and was pressed to provide a secondary battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing DBNO radical as a
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positive electrode and the copper foil with a lithium film
as a negative electrode, indicating its action as a
secondary battery. Repeated charge/discharge for the
secondary battery indicated that the battery acted as a
secondary battery capable of charge/discharge for 10 cycles
or more.
Example 8
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of diphenylnitroxyl
radical (DPNO radical) having the molecular structure
represented by chemical formula (A21) and 60 mg of graphite
powder as a conductive adjuvant under an atmosphere of
argon. To the mixture were added 20 mg of a copolymer of
vinylidene fluoride and hexafluoropropylene and 1 g of
tetrahydrofuran, and the mixture was stirred for several
minutes until it became homogeneous to provide a black
slurry. A sample of DPNO radical used was subject to
electron spin resonance spectroscopy as described in
Example 1 to give a spin concentration of 1021 spin/g or
more.
(A21)
N-O =
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CA 02617291 2008-01-24
Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
cmxl.5 cm, thickness: 100 m) with a lead, and the slurry
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing DPNO radical on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing DPNO radical had been formed. On
the foil was then laminated a copper foil having a lithium
film with a lead (thickness: 30Eun for the lithium film and
20Eun for the copper foil). The whole product was sandwiched
with polytetrafluoroethylene sheets with a thickness of 5
mm and was pressed to provide a secondary battery.
For a sample of the secondary battery thus prepared,
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discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing DPNO radical as a
positive electrode and the copper foil with a lithium film
as a negative electrode, indicating its action as a
secondary battery. Repeated charge/discharge for the
secondary battery indicated that the battery acted as a
secondary battery capable of charge/discharge for 10 cycles
or more.
Example 9
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of 3-amino-2,2,6,6-
tetramethylpyrrolidinoxyl radical (TEMPO(3 radical) having
the molecular structure represented by chemical formula
(A33) and 60 mg of graphite powder as a conductive adjuvant
under an atmosphere of argon. To the mixture were added 20
mg of a copolymer of vinylidene fluoride and
hexafluoropropylene and 1 g of tetrahydrofuran, and the
mixture was stirred for several minutes until it became
homogeneous to provide'a black slurry. A sample of the
radical used was subject to electron spin resonance
spectroscopy as described in Example 1 to give a spin
concentration of 1021 spin/g or more.
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(A33) NH2
N
I
O
Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
cmxl.5 cm, thickness: 100 m) with a lead, and the slurry
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing TEMPOP radical on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing TEMPO(3 radical had been formed.
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On the foil was then laminated a copper foil having a
lithium film with a lead (thickness: 30Eun for the lithium
film and 20Eun for the copper foil). The whole product was
sandwiched with polytetrafluoroethylene sheets with a
thickness of 5 mm and was pressed to provide a secondary
battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing TEMPO(3 radical as a
positive electrode and the copper foil with a lithium film
as a negative electrode, indicating its action as a
secondary battery. Repeated charge/discharge for the
secondary battery indicated that the battery acted as a
secondary battery capable of charge/discharge for 10 cycles
or more.
Example 10
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of 3-amino-2,2,6,6-
tetramethylpyrrolinoxyl radical (TEMPOy radical) having the
molecular structure represented by chemical formula (A39)
and 60 mg of graphite powder as a conductive adjuvant under
an atmosphere of argon. To the mixture were added 20 mg of
a copolymer of vinylidene fluoride and hexafluoropropylene
and 1 g of tetrahydrofuran, and the mixture was stirred for
several minutes until it became homogeneous to provide a
black slurry. A sample of TEMPOy radical used was subject
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CA 02617291 2008-01-24
to electron spin resonance spectroscopy as described in
Example 1 to give a spin concentration of 1021 spin/g or
more.
(A 3 9) NH2
N
I
0
.
Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
cmxl.5 cm, thickness: 100pun) with a lead, and the slurry
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing TEMPOy radical on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
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cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing TEMPOy radical had been formed.
On the foil was then laminated a copper foil having a
lithium film with a lead (thickness: 30Eun for the lithium
film and 20Eun for the copper foil). The whole product was
sandwiched with polytetrafluoroethylene sheets with a
thickness of 5 mm and was pressed to provide a secondary
battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing TEMPOy radical as a
positive electrode and the copper foil with a lithium film
as a negative electrode, indicating its action as a
secondary battery. Repeated charge/discharge for the
secondary battery indicated that the battery acted as a
secondary battery capable of charge/discharge for 10 cycles
or more.
Example 11
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of
nitronylnitroxide compound (NONO) having the molecular
structure represented by chemical formula (A43) and 60 mg
of graphite powder as a conductive adjuvant under an
atmosphere of argon. To the mixture were added 20 mg of a
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copolymer of vinylidene fluoride and hexafluoropropylene
and 1 g of tetrahydrofuran, and the mixture was stirred for
several minutes until it became homogeneous to provide a
black slurry. A sample of NONO used was subject to electron
spin resonance spectroscopy as described in Example 1 to
give a spin concentration of 1021 spin/g or more.
(A43) 00
,
N
N-N
N
Q
.
Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
cmxl.5 cm, thickness: 100pun) with a lead, and the slurry
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing NONO on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
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on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing NONO had been formed. On the
foil was then laminated a copper foil having a lithium film
with a lead ( thickness : 30Eun for the lithium film and 20Nzn
for the copper foil). The whole product was sandwiched with
polytetrafluoroethylene sheets with a thickness of 5 mm and
was pressed to provide a secondary battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing NONO as a positive
electrode and the copper foil with a lithium film as a
negative electrode, indicating its action as a secondary
battery. Repeated charge/discharge for the secondary
battery indicated that the battery acted as a secondary
battery capable of charge/discharge for 10 cycles or more.
Example 12
In a glass vessel in a dry box equipped with a gas
purifier were sequentially placed 50 mg of galvinoxyl
having the molecular structure represented by chemical
formula B5 and 60 mg of graphite powder as a conductive
adjuvant under an atmosphere of argon. To the mixture were
added 20 mg of a copolymer of vinylidene fluoride and
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hexafluoropropylene and 1 g of tetrahydrofuran, and the
mixture was stirred for several minutes until it became
homogeneous to provide a black slurry. A sample of
galvinoxyl used was subject to electron spin resonance
spectroscopy as described in Example 1 to give a spin
concentration of 1021 spin/g or more, which indicated that
the sample has the structure having an oxy radical
represented by chemical formula 5 in an initial state.
B 5
o c O o.
_H 10 Then, 200 mg of the slurry thus obtained was added
dropwise on the surface of an aluminum foil (area: 1.5
cmxl.5 cm, thickness: 100Eun) with a lead, and the slurry
was spread using a wire bar such that the overall surface
became even. It was left for 60 min at room temperature to
evaporate the solvent, tetrahydrofuran, and to form a layer
containing galvinoxyl on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene were added 1400 mg of the 1:1 mixture
of ethylene carbonate / propylene carbonate containing 1
mol/L of LiPF6 as an electrolyte salt and then 11.3 g of
tetrahydrofuran, and the mixture was stirred at room
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temperature. After dissolving the copolymer of vinylidene
fluoride and hexafluoropropylene, the mixture was applied
on a stepped glass plate. It was left for 1 hour for
spontaneous evaporation of tetrahydrofuran to provide a
cast film with a thickness of 1 mm.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil prepared above on which an
electrode layer containing galvinoxyl radical had been
formed. On the foil was then laminated a copper foil having
a lithium film with a lead (thickness: 30Eun for the lithium
film and 20Eun for the copper foil). The whole product was
sandwiched with polytetrafluoroethylene sheets with a
thickness of 5 mm and was pressed to provide a secondary
battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing galvinoxyl radical as
a positive electrode and the copper foil with a lithium
film as a negative electrode. The results showed a voltage
plateau at about 2.3 V, indicating its action as a
secondary battery. Repeated charge/discharge for the
secondary battery indicated that the battery acted as a
secondary battery capable of charge/discharge for 10 cycles
or more. A part of the positive electrode layer was removed
from the sample after discharge and was subject to electron
spin resonance spectroscopy to give a spin concentration of
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1019 spin/g or less. It suggested that after discharge,
galvinoxyl radical was consumed due to its formation of a
bond with lithium ion.
Example 13
Fifty milligrams of poly(vinyl-di-tert-butylphenol)
was treated with equimolar potassium ferricyanide and
sodium hydroxide to provide poly(vinyl-di-tert-butylphenoxy
radical). The product was subject to electron spin
resonance spectroscopy as described in Example 1 to give a
spin concentration of 1021 spin/g or more. The results
indicated that the product has the structure having an oxy
radical represented by chemical formula B10 in an initial
state.
B10
nn
O=
A conductive adjuvant, a copolymer of vinylidene
fluoride-hexafluoroethylene and tetrahydrofuran were mixed
as described in Example 12, substituting poly(vinyl-di-
tert-butyiphenoxy radical) for galvinoxyl to provide a
black slurry. Then, on an aluminum foil was formed a
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compound layer containing poly(vinyl-di-tert-butylphenoxy
radical) as described in Example 12.
On the aluminum foil comprising poly(vinyl-di-tert-
butylphenoxy radical) was laminated a cast film cut by 2.0
cmx2.0 cm prepared from a mixed solution of ethylene
carbonate and propylene carbonate containing 1 mol/L of
LiPF6 as an electrolyte salt in Example 12 and a copolymer
electrolyte of vinylidene fluoride and hexafluoropropylene.
On the product was then laminated lithium as described in
Example 12 to provide a secondary battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing poly(vinyl-di-tert-
butylphenoxy radical) as a positive electrode and the
copper foil with a lithium film as a negative electrode.
The results showed a voltage plateau at about 2.4 V,
indicating its action as a secondary battery. Voltage
variation with charge/discharge of the secondary battery
was measured. The results indicated that the battery acted
as a secondary battery. A part of the positive electrode
layer was removed from the sample after discharge and was
subject to electron spin resonance spectroscopy to give a
spin concentration of 1019 spin/g or less. It suggested
that after discharge, poly(vinyl-di-tert-butylphenoxy
radical) in the positive electrode was consumed due to, for
example, its formation of a bond with lithium ion.
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Example 14
Acetyl-di-tert-butylphenol was reacted with
molybdenum pentachioride in benzene at 40 C to prepare
poly(3,5-di-tert-butyl-4-hydroxyphenylacetylene). It was
treated with potassium ferricyanide and sodium hydroxide as
described in Example 13 to provide poly(acetyl-di-tert-
butylphenoxy radical). The product was subject to electron
spin resonance spectroscopy as described in Example 1 to
give a spin concentration of 1021 spin/g or more. The
results indicated that the product has the structure having
an oxy radical represented by chemical formula B12 in an
initial state.
B12
nn
0
o-
A conductive adjuvant, a copolymer of vinylidene
fluoride-hexafluoroethylene and tetrahydrofuran were mixed
as described in Example 12, substituting poly(acetyl-di-
tert-butylphenoxy radical) for galvinoxyl to provide a
black slurry. Then, on an aluminum foil was formed a
compound layer containing poly(acetyl-di-tert-butylphenoxy
radical) as described in Example 12.
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On the aluminum foil comprising poly(acetyl-di-tert-
butylphenoxy radical) was laminated a cast film cut by 2.0
cmX2.0 cm prepared from a mixed solution of ethylene
carbonate and propylene carbonate containing 1 mol/L of
LiPF6 as an electrolyte salt in Example 12 and a copolymer
electrolyte of vinylidene fluoride and hexafluoropropylene.
On the product was then laminated lithium as described in
Example 12 to provide a secondary battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing poly(acetyl-di-tert-
butyiphenoxy radical) as a positive electrode and the
copper foil with a lithium film as a negative electrode.
The results showed a voltage plateau at about 3.3 V,
indicating its action as a secondary battery. Voltage
variation with charge/discharge of the secondary battery
was measured. The results indicated that the battery acted
as a secondary battery. A part of the positive electrode
layer was removed from the sample after discharge and was
subject to electron spin resonance spectroscopy as
described in Example 1 to give a spin concentration of 1019
spin/g or less. It suggested that after discharge,
poly(acetyl-di-tert-butylphenoxy radical) in the positive
electrode was consumed due to, for example, its formation
of a bond with lithium ion.
Example 15
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In an electrolysis cell was placed a solution or
dispersion of 0.25 M of LiAsF6, 0.25 M of CuC12 and 0.5 M
of benzene in nitrobenzene. Two platinum plates were
inserted into the solution/dispersion and electrolysis was
conducted at a voltage of 10 V to form a conductive
poly(paraphenylene) film with a film thickness of 10 m on
the surface of the positive electrode. At the end of the
reaction, the electrodes were short-circuited and the film
was then removed from the electrode. The
poly(paraphenylene) film was placed in a vacuum vessel,
heated to 450 C with 0.1 mol of oxygen to its monomer unit
and kept at the temperature for 2 hours. The film was
cooled to room temperature to obtain a sample. NMR and IR
spectra for the sample suggested the molecular structure of
the semiquinone represented by chemical formula B9 in which
a part of the poly(paraphenylene) was replaced with oxygen.
ESR spectrum gave a spin concentration of 2x1021 spin/g for
the sample.
B9
0
n
eo
The sample having the semiquinone structure was
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directly laminated on an aluminum foil and the product was
pressed. On the aluminum foil was laminated a cast film cut
by 2.0 cmx2.0 cm prepared from a mixed solution of ethylene
carbonate and propylene carbonate containing 1 mol/L of
LiPF6 as an electrolyte salt in Example 12 and a copolymer
electrolyte of vinylidene fluoride and hexafluoropropylene.
On the product was then laminated lithium as described in
Example 12 to provide a secondary battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode comprising the compound having the
semiquinone structure as a positive electrode and the
copper foil with a lithium film as a negative electrode.
The results showed a voltage plateau at about 3.1 V,
indicating its action as a secondary battery. Voltage
variation with charge/discharge of the secondary battery
was measured. The results indicated that the battery acted
as a secondary battery. A part of the positive electrode
layer was removed from the sample after discharge and was
subject to electron spin resonance spectroscopy to give a
spin concentration of 1019 spin/g or less. It suggested
that after discharge, the compound having the semiquinone
structure in the positive electrode was consumed due to,
for example, its formation of a bond with lithium ion.
Example 16
In an electrolysis cell was placed powdered 1,3,5-
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trisdiazo-cyclohexane-2,4,6-trione, which was then heated
to 600 C and kept at the temperature for 20 hours. The
reaction was cooled to room temperature to obtain a sample.
NMR and IR spectra for the sample suggested a network
polyoxy radical whose molecular structure had the basic
structure represented by chemical formula B4. ESR spectrum
gave a spin concentration of 8x1021 spin/g for the sample.
B4 R
Q / d
(
R \ R
0
A conductive adjuvant, a copolymer of vinylidene
fluoride-hexafluoroethylene and tetrahydrofuran were mixed
as described in Example 12, substituting the presumably
network polyoxy radical for galvinoxyl to provide a black
slurry. Then, on an aluminum foil was formed a compound
layer containing the presumably network polyoxy radical as
described in Example 12.
On the aluminum foil comprising the presumably
network polyoxy radical was laminated a cast film cut by
2.0 cmx2.0 cm prepared from a mixed solution of ethylene
carbonate and propylene carbonate containing 1 mol/L of
LiPF6 as an electrolyte salt in Example 12 and a copolymer
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electrolyte of vinylidene fluoride and hexafluoropropylene.
On the product was then laminated lithium as described in
Example 12 to provide a secondary battery.
For a sample of the secondary battery thus prepared,
discharge with a constant current of 0.1 mA was conducted
using the electrode layer containing the presumably network
polyoxy radical as a positive electrode and the copper foil
with a lithium film as a negative electrode. The results
showed a voltage plateau at about 3.3 V, indicating its
action as a secondary battery. Voltage variation with
charge/discharge of the secondary battery was measured. The
results indicated that the battery acted as a secondary
battery. A part of the positive electrode layer was removed
from the sample after discharge and was subject to electron
spin resonance spectroscopy as described in Example 1 to
give a spin concentration of 1019 spin/g or less. It
suggested that after discharge, the presumably network
polyoxy radical in the positive electrode was consumed due
to, for example, its formation of a bond with lithium ion.
Example 17
There will be described a process for preparing a
secondary battery using diphenylpicrylhydrazyl represented
by chemical formula (C29) as an active material. In advance,
diphenylpicrylhydrazyl was subject to electron spin
resonance spectroscopy to give a spin concentration of 1021
spin/g or more.
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~ No2
N- NC)2 {C29}
d NU2
In a dry box equipped with a gas purifier were mixed
60 mg of a copolymer of vinylidene fluoride and
hexafluoropropylene and 140 mg of an electrolyte solution
which was a 1:1 mixture of ethylene carbonate / propylene
carbonate containing 1 mol/L of LiPF6 electrolyte salt
under an atmosphere of argon gas. To the mixture was added
1130 mg of tetrahydrofuran, and the mixture was dissolved
to prepare a solution of a gel electrolyte in
tetrahydrofuran. In a separate glass vessel was placed 30
mg of diphenylpicrylhydrazyl, then 60 mg of graphite powder
as a conductive adjuvant and then 200 mg of the abovesolution of a gel
electrolyte in tetrahydrofuran as an ion-
conductive adjuvant, and the mixture was blended. To the
mixture was added 1000 mg of tetrahydrofuran and the
mixture was further stirred for 3 hours to provide a black
slurry. Then, 200 mg of the slurry was added dropwise on
the surface of an aluminum foil (area: 1.5 cmxl.5 cm,
thickness: 100p.m) with a lead, and the slurry was spread
using a wire bar such that the overall surface became even.
It was left for 3 hours at room temperature to
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substantially evaporate the solvent, tetrahydrofuran, and
to form an electrode layer containing
diphenylpicrylhydrazyl on the aluminum foil.
To 600 mg of a copolymer of vinylidene fluoride-
hexafluoropropylene were added 1400 mg of an electrolyte
solution, i.e., a 1:1 mixed solution of ethylene carbonate
/ propylene carbonate containing 1 mol/L of LiPF6 as an
electrolyte salt and 11.3 g of tetrahydrofuran, and the
mixture was stirred at room temperature. After dissolving
the copolymer of vinylidene fluoride-hexafluoropropylene,
the solution was applied on a glass plate with a glass
frame. The plate was dried in the air to evaporate
tetrahydrofuran to provide a cast film with a thickness of
300 m on the glass plate.
The gel electrolyte film cut by 2.0 cmx2.0 cm was
laminated on the aluminum foil on which
diphenylpicrylhydrazyl had been formed. On the foil was
then laminated a copper foil having a lithium film with a
lead (thickness: 30 m for the lithium film and 20pn for the
copper foil) . The whole product was sandwiched with
polytetrafluoroethylene sheets with a thickness of 5 mm and
was pressed to provide a secondary battery.
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
electrode layer containing diphenylpicrylhydrazyl as a
positive electrode and the copper foil with a lithium film
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as a negative electrode. A voltage was constant at about
2.5 V for about 5 hours and it took additional 12 hours for
a voltage to be reduced to I V or less. It was found that a
voltage was kept constant at about 2.5 V after 10 cycles of
charge/discharge, indicating that the battery acted as a
secondary battery. A part of the positive electrode layer
cut from the sample after discharge was subject to electron
spin resonance spectroscopy to give a spin concentration of
1019 spin/g or less. It would be because
diphenylpicrylhydrazyl was converted into a compound
without a radical in an electrode reaction during discharge.
It was thought that diphenylpicrylhydrazyl acted as an
active material in the positive electrode for action of the
secondary battery.
Example 18
A secondary battery was prepared as described in
Example 17, substituting triphenylpherdazyl having the
molecular structure represented by chemical formula (C30)
for diphenylpicrylhydrazyl, and discharge was conducted. In
advance, triphenylpherdazyl was subject to electron spin
resonance spectroscopy to give a spin concentration of 1021
spin/g or more.
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(C30)
r N-
N-
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
aluminum foil comprising a compound layer containing
triphenylpherdazyl as a positive electrode and the copper
foil with a lithium film as a negative electrode. A plateau
was found at about 2.3 V and it took 8 hours for a voltage
to be reduced to 1 V or less. A part of the positive
electrode layer cut from the sample after discharge was
subject to electron spin resonance spectroscopy to give a
spin concentration of 1019 spin/g or less. It would be
because triphenylpherdazyl was converted into a compound
without a radical in an electrode reaction during discharge.
It was thought that triphenylpherdazyl acted as an active
material in the positive electrode for action of the
secondary battery.
Example 19
A secondary battery was prepared as described in
Example 17, substituting a polymer compound having the
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pherdazyl structure represented by chemical formula (C31)
for diphenylpicrylhydrazyl, and discharge was conducted. In
advance, the polymer compound having the molecular
structure represented by chemical formula (C31) was subject
to electron spin resonance spectroscopy to give a spin
concentration of 1021 spin/g or more.
0
(C31)
No N
I I
N,,~N
00
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
aluminum foil comprising the layer of the polymer compound
having the molecular structure represented by chemical
formula (C31) and the copper foil with a lithium film as a
negative electrode. A plateau was found at about 2.3 V and
it took 12 hours for a voltage to be reduced to 1 V or less.
Example 20
A secondary battery was prepared as described in
Example 17, substituting a polymer compound having the
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aminotriazine structure represented by chemical formula
(C32) for diphenylpicrylhydrazyl, and discharge was
conducted. In advance, the polymer compound having the
molecular structure represented by chemical formula (C32)
was subject to electron spin resonance spectroscopy to give
a spin concentration of 1021 spin/g or more.
0
0
(C3 2)
)-1-'
N N
0 N
~ ~
~.
N N N N
For the secondary battery thus prepared, discharge
with a constant current of 0.1 mA was conducted using the
aluminum foil comprising the layer of the polymer compound
having the molecular structure represented by chemical
formula (C32) and the copper foil with a lithium film as a
negative electrode. A plateau was found at about 2.3 V and
it took 10 hours for a voltage to be reduced to I V or less.
Comparative Example 2
A secondary battery was prepared as described in
Example 17, without using a compound having a radical on a
nitrogen atom as an active material, and discharge was
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conducted at a constant current of 0.1 mA. A voltage was
rapidly reduced to 0.8 V in about 50 min. In attempting
charge by applying a constant current of 0.1 mA, a voltage
was momentarily increased over 3.0 V and during re-
discharge was rapidly reduced to 0.8 V in about 50 mi.n. It
indicated that the battery did not act as a secondary
battery.
Example 21
On the aluminum foil comprising an organic compound
layer containing TEMPO radical prepared in Example 1 were
laminated the gel electrolyte film as described in Example
1 and then a copper foil having a lithium film with a lead.
The whole product was sandwiched with
polytetrafluoroethylene sheets with a thickness of 5 mm and
was pressed to provide a secondary battery.
For the secondary battery thus prepared, charge with
a constant current of 0.1 mA was conducted using the
aluminum foil comprising an organic compound layer
containing TEMPO radical as a positive electrode and the
copper foil with a lithium film as a negative electrode. A
voltage plateau was found at about 3.5 V, indicating that
the battery acted as a secondary battery. A part of the
compound layer containing TEMPO radical cut from the sample
after discharge was subject to electron spin resonance
spectroscopy as described in Example 1 to give a spin
concentration of 1019 spin/g or less. It may indicate that
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~'370-101
after charge, TEMPO radical formed a bond with an
electrolyte anion to consume radical. After discharging the
secondary battery at a constant current of 0.1 mA, it was
subject to electron spin resonance spectroscopy to give a
spin concentration of 1021 spin/g or more, suggesting that
in the positive electrode, discharge caused cleavage of the
bond with the electrolyte anion to form a radical compound.
A secondary battery was prepared as described above
for measuring voltage variation with charge/discharge. The
battery exhibited a plateau in its discharge curve even
after repeated charge/discharge; in other words, it also
acted as a secondary battery.
As described above, a radical compound is used as a
material involved in an electrode reaction according to
this invention, so that there can be provided a stable
secondary battery with a higher energy density and a larger
capacity.
131
