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Patent 2326175 Summary

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(12) Patent Application: (11) CA 2326175
(54) English Title: LITHIUM BATTERY AND ELECTRODE
(54) French Title: BATTERIE AU LITHIUM ET ELECTRODE
Status: Dead
Bibliographic Data
(51) International Patent Classification (IPC):
  • H01M 4/36 (2006.01)
  • H01M 4/02 (2006.01)
  • H01M 4/60 (2006.01)
  • H01M 4/58 (2010.01)
  • H01M 4/62 (2006.01)
  • H01M 10/36 (2010.01)
  • H01M 4/58 (2006.01)
(72) Inventors :
  • OGURA, SHIZUO (Japan)
  • MOKUDAI, HIDEHISA (Japan)
  • MURATA, MAKOTO (Japan)
  • DAVIES, BARRIE LINTON (United States of America)
(73) Owners :
  • AXIVA GMBH (Germany)
(71) Applicants :
  • AXIVA GMBH (Germany)
(74) Agent: SMART & BIGGAR IP AGENCY CO.
(74) Associate agent:
(45) Issued:
(86) PCT Filing Date: 1999-03-23
(87) Open to Public Inspection: 1999-10-07
Examination requested: 2003-12-22
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/EP1999/001945
(87) International Publication Number: WO1999/050922
(85) National Entry: 2000-09-26

(30) Application Priority Data:
Application No. Country/Territory Date
09/052,365 United States of America 1998-03-31
134350/98 Japan 1998-04-28

Abstracts

English Abstract




An electrode includes an electrically conductive matrix containing a disulfide
group, wherein an S-S bond of the disulfide group is cleaved by
electrochemical reduction and reformed by electrochemical oxidation. A
plurality of carbon nanotubes is dispersed in the electrically conductive
matrix. The electrode can be used as a cathode of a lithium battery.


French Abstract

Electrode comprenant une matrice conductrice électriquement et contenant un groupe disulfure dont une liaison S-S est divisée par réduction électrochimique et reconstituée par oxydation électrochimique. Une pluralité de nanotubes de carbone est dispersée dans la matrice conductrice électriquement. On peut mettre en application cette électrode en tant que cathode d'une batterie au lithium.

Claims

Note: Claims are shown in the official language in which they were submitted.




20
What is claimed is:
1. An electrode, comprising:
an electrically conductive matrix containing a disulfide group, wherein an S-S
bond of the disulfide group is cleaved by electrochemical reduction and
reformed by electrochemical oxidation; and
a plurality of carbon nanotubes being dispersed in the electrically conductive
matrix.
2. An electrode of claim 1 wherein the electrically conductive matrix contains
an
electrically conductive polymer and an organic compound having the disulfide
group.
3. An electrode of claim 2 wherein the electrically conductive polymer
comprises
a polymer represented by a formula:
-[Ar-NH]n-
wherein Ar is aryl, and n is an integer.
4. An electrode of claim 2 wherein the electrically conductive polymer
comprises
polyaniline.
5. An electrode of claim 2 wherein the organic compound contains a 5 to 7
membered, heterocyclic ring containing 1 to 3 heteroatoms consisting of a
nitrogen atom and a sulfur atom.
6. An electrode of claim 2 wherein the organic compound contains a thiadiazole
ring.
7. An electrode of claim 1 wherein the electrically conductive matrix contains
an
electrically conductive polymer having the mercapto group which is capable of
forming disulfide group.
8. An electrode of claim 1 wherein the electrode contains 0.5 to 6 percent by
weight of the carbon nanotubes based on a sum of the electrically conductive
matrix and the carbon nanotubes.
9. An electrode of claim 1 wherein the electrode contains 1 to 4 percent by
weight



21
of the carbon nanotubes based on a sum of the electrically conductive matrix
and the carbon nanotubes.
10. An electrode of claim 1 wherein the carbon nanotubes have an average
diameter of 3.5 to 200 nanometers and an average length of 0.1 to 500
micrometers.
11. An electrode of claim 1 wherein the carbon nanotubes have an average
diameter of 5 to 30 nanometers and an average length of 100 to 10000 times
the diameter thereof.
12. A battery precursor, comprising:
(a) a cathode having:
an electrically conductive matrix containing a disulfide group, wherein an
S-S bond of the disulfide group is cleaved by electrochemical reduction
and reformed by electrochemical oxidation; and
a plurality of carbon nanotubes being dispersed in the electrically
conductive matrix; and
(b) a cathode current collector;
wherein the cathode is coated onto the cathode current collector.
13. A battery precursor of claim 12 wherein the cathode current collector and
the
cathode have a layered structure.
14. A battery precursor of claim 12 wherein the cathode has a thickness
ranging
from 5 to 500 micrometers.
15. A battery precursor of claim 12 wherein the cathode has a thickness
ranging
from 10 to 100 micrometers.
16. A battery precursor of claim 12 wherein the cathode current collector has
a
sheet configuration.
17. A battery precursor of claim 12 wherein the cathode current collector
comprises a metallic foil.
18. A battery precursor of claim 12 wherein the electrically conductive matrix
contains an electrically conductive polymer and an organic compound having



22
the disulfide group.
19. A battery precursor of claim 18 wherein the electrically conductive
polymer
comprises a polymer represented by a formula:
-[Ar-NH]n-
wherein Ar is aryl, and n is an integer.
20. A battery precursor of claim 18 wherein the organic compound contains a 5
to
7 membered, heterocyclic ring containing 1 to 3 heteroatoms consisting of a
nitrogen atom and a sulfur atom.
29. A battery precursor of claim 12 wherein the electrically conductive matrix
contains an electrically conductive polymer having the mercapto group which is
capable of forming the disulfide group.
22. A battery precursor of claim 12 wherein the cathode contains 0.5 to 6
percent
by weight of the carbon nanotubes based on a sum of the electrically
conductive matrix and the carbon nanotubes.
23. A battery precursor of claim 12 wherein the carbon nanotubes have an
average diameter of 3.5 to 200 nanometers and an average length of 0.1 to
500 micrometers.
24. A lithium battery, comprising:
(a) a cathode having:
an electrically conductive matrix containing a disulfide group, wherein an
S-S bond of the disulfide group is cleaved by electrochemical reduction
and reformed by electrochemical oxidation; and
a plurality of carbon nanotubes being dispersed in the electrically
conductive matrix;
(b) an anode having an active material for releasing lithium ions; and
(c) an electrolyte being disposed between the cathode and the anode.
25. A lithium battery of claim 24, further comprising:
(d) a cathode current collector contacting with the cathode; and
(e) an anode current collector contacting with the anode.


23

26. A lithium battery of claim 25 wherein the cathode current collector, the
cathode, the electrolyte, the anode, and the anode current collector have a
layered structure and are laminated each other in this order.
27. A lithium battery of claim 24, wherein the electrolyte comprises at least
one of
a solid electrolyte and a gel electrolyte.
28. A lithium battery of claim 24 wherein the electrically conductive matrix
contains
an electrically conductive polymer and an organic compound having the
disulfide group.
29. A lithium battery of claim 28 wherein the electrically conductive polymer
comprises a polymer represented by a formula:
-[Ar-NH]n-
wherein Ar is aryl, and n is an integer.
30. A lithium battery of claim 28 wherein the organic compound contains a 5 to
7
membered, heterocyclic ring containing 1 to 3 heteroatoms consisting of a
nitrogen atom and a sulfur atom.
31. A lithium battery of claim 24 wherein the electrically conductive matrix
contains
an electrically conductive polymer having the mercapto group which is capable
of forming disulfide group.
32. A lithium battery of claim 24 wherein the cathode contains 0.5 to 6
percent by
weight of the carbon nanotubes based on a sum of the electrically conductive
matrix and the carbon nanotubes.
33. A lithium battery of claim 24 wherein the carbon nanotubes have an average
diameter of 3.5 to 200 nanometers and an average length of 0.1 to 500
micrometers.
34. A lithium battery of claim 24 wherein the cathode has a thickness ranging
from
to 500 micrometers.

Description

Note: Descriptions are shown in the official language in which they were submitted.



CA 02326175 2000-09-26
WO 99/50922 PCT/EP99I01945
1
Lithium Battery and Electrode
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrode, a battery precursor and a
lithium
battery.
2. Description of Related Art
Batteries are a type of electrochemical cell containing a pair of electrodes
and
an electrolyte disposed between the electrodes. One of the electrodes is
called a cathode wherein an active material is reduced during discharge. The
other electrode is called an anode wherein another active material is oxidized
during discharge. Secondary batteries refer to batteries capable of charging
electricity after discharge.
Recently, intensive research has been conducted on lithium secondary
batteries because of their high voltage and high energy density. Lithium
batteries refers to batteries having an anode containing an active material
for
releasing lithium ions during discharge. The active material may be metallic
lithium and an intercalated material being capable of incorporating lithium
between layers.
Particular attention has been paid to an electrode material for the cathode of
the lithium secondary battery. For example, U.S. Patent No. 4,833,048
discloses a cathode containing a disulfide compound for improving an energy
density. This compound is represented by R-S-S-R wherein R is an aliphatic
or an aromatic organic group and S is a sulfur atom. An S-S bond is cleaved
by the electrolytic reduction in an electrolytic cell containing ration of M+
to
form a salt represented by R-S-~M+. This salt returns to the R-S-S-R by the
electrolytic oxidation. U.S. Patent No. 4,833,048 discloses a rechargeable
battery obtained by combining a disulfide compound with metal M which
supplies and captures the rations (M''). The rechargeable battery provides an
improved energy density of at least 150 Whlkg. The entire disclosure of U.S.
Patent No. 4,833,048 is incorporated herein as reference.
However, as the inventors of U.S. Patent No. 4,833,048 reported in J.
Electrochem. Soc., Vol. 136, No. 9, pp. 2570 to 2575 (1989), the difference
between the oxidation potential and the reduction potential of the disulfide
compound is very large. For example, when [(C2Hs)zNCSS-]2 is electrolyzed,
w


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
2
the oxidation potential differs from the reduction potential by 1 V or more.
According to the theory of electrochemical reaction, the electron transfer of
the
disulfide compound proceeds extremely slowly at room temperature.
Therefore, it is rather difficult to obtain a rechargeable battery providing a
higher current output of 1 mA/cm2 or more at room temperature. The operation
of a battery comprising an electrode of disulfide compound is limited to high
temperatures in the range of 100° to 200°C, where the electron
transfer can
proceed faster.
U.S. patent No. 5,324,599 discloses a cathode for a lithium secondary battery
containing the disulfide compound and a conductive polymer. The conductive .
polymer allows to operate the battery in much lower temperatures such as
room temperature. The entire disclosure of U.S. patent No. 5,324,599 is
incorporated herein as reference.
Japanese Patent No. 2,513,418, which corresponds to JP-A-5-175929,
discloses a cathode containing carbon nanotubes. The carbon nanotubes are
obtained by electric discharge between a pair of carbon rods. Japanese Patent
No. 2,513,418 does not teach the disulfide compound. The entire disclosure of
Japanese Patent No. 2513418 is incorporated herein as reference.
WO 95/07551 discloses an electrode, which may be used for a lithium
secondary battery, containing carbon nanotubes. The carbon nanotubes are
obtained by catalytic reactions. The document further discloses aggregates of
carbon nanotubes disentangled by an ultrasonic homogenizer. The entire
disclosure of WO 95/07551 is incorporated herein as reference.
SUMMARY OF THE INVENTION
According to the first aspect of the present invention, there is provided an
electrode,
comprising: an electrically conductive matrix containing a disulfide group,
wherein
an S-S bond of the disulfide group is cleaved by electrochemical reduction and
reformed by electrochemical oxidation; and a plurality of carbon nanotubes
being
dispersed in the electrically conductive matrix.
Preferably, the electrically conductive matrix may contain an electrically
conductive
polymer and an organic compound having the disulfide group. Alternatively, the
electrically conductive matrix may contain an electrically conductive polymer
having
the mercapto group which is capable of forming disulfide group.
According to the second aspect of the present invention, there is provided a
battery
precursor, comprising: a cathode having: an electrically conductive matrix
containing a disulfide group, wherein an S-S bond of the disulfide group is
cleaved
by electrochemical reduction and reformed by electrochemical oxidation; and a


CA 02326175 2000-09-26
WO 99/50922 PG"f/EP99/01945
3
plurality of carbon nanotubes being dispersed in the electrically conductive
matrix;
and a cathode current collector; wherein the cathode is coated onto the
cathode
current collector.
According to the third aspect of the present invention, a lithium battery,
comprising:
a cathode having: an electrically conductive matrix containing a disulfide
group,
wherein an S-S bond of the disulfide group is cleaved by electrochemical
reduction
and reformed by electrochemical oxidation; and a plurality of carbon nanotubes
being dispersed in the electrically conductive matrix; an anode having an
active
material for releasing lithium ions; and an electrolyte being disposed between
the
cathode and the anode.
Brief Description of the Drawings
Fig. 1 is a cross section of a part of a homogenizer.
Fig. 2 is a photograph of a poly(methylmethacrylate) film containing
disentangled
carbon nanotubes observed by transmission electron microscopy.
Fig. 3 is a photograph of a poly(methylmethacrylate) film containing
aggregates of
carbon nanotubes observed by transmission electron microscopy.
Fig. 4 is a cross section of a laminated structure used for a lithium battery.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An electrode of the present invention includes an electrically conductive
matrix
containing a disulfide group. In one embodiment, the electrically conductive
matrix
contains an electrically conductive polymer and an organic compound having the
disulfide group. In another embodiment, the electrically conductive matrix
contains
an electrically conductive polymer having the mercapto group.
The disulfide group is responsible for the electrochemical reactions at the
electrode.
Namely, an S-S bond of the disulfide group is cleaved by electrochemical
reduction
and reformed by electrochemical oxidation. When the electrode is used as a
cathode for a lithium battery, the electrochemical reactions of the cathode
and an
anode are shown in the formula as follows:


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
4
discharge:oxidation
anode: Li ~- Li+ + e'
charge: reduction
discharge: reduction
cathode: R-S-S-R + 2Li+ + 2e- ~ 2R-S-Li
charge:oxidation
wherein R-S-S-R is an organic compound having the disulfide group, R is an
aliphatic or an aromatic organic group, and S is a sulfur atom.
In this example, metallic lithium is used as the anode although the anode of a
lithium
battery is not limited to metallic lithium. When the lithium battery
discharges,
electrochemical reduction occurs at the cathode, and the organic compound
containing the disulfide group reacts with lithium ions to cleave an S-S bond
of the
disulfide group thereof and to form a salt represented by R-S'~Li+. During the
discharge, electrochemical oxidation occurs at the anode, and a metallic
lithium is
oxidized to a lithium ion.
When the lithium battery is charged, the reactions proceed in reverse
directions.
Specifically, electrochemical oxidation occurs at the cathode, and the salt
returns to
the R-S-S-R; electrochemical reduction occurs at the anode, and the lithium
ion
returns to the metallic lithium.
Examples of the organic compound having the disulfide group are shown in
Tables
1 and 2.
Name Formula
2-mercaptoethyl ether (-SCHZCH20CH2CH2S-)~
dimercapto dithiazole
N N
S- ~ /C S
/S
n


CA 02326175 2000-09-26
WO 99/50921 PCT/EP99/01945
dimethyl ethylenediamine
CH3 CH3
S NCH2CHZN S
n
ethylenediamine
-s\ / s
NCH2CH2N
-S~ \S-
n
polyethylene
5 imine derivative
CH2NCH2
S
S
CH2NCH2
n
trithiocyanuric acid
s
C\
N~ \ N
-S \ N ~ C S
n


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
6
piperazine
S ~ S
n
2,4-dithiopyrimidine
O~~ ~~
1,2~thanedithiiol (-SCHZ-CHZS-)~
2-mercaptoethyl sulfide (-SCH2CH2SCH2CH2S-)~
Preferably, the organic compound contains a 5 to 7 membered, heterocyclic ring
containing 1 to 3 heteroatoms consisting of a nitrogen atom and a sulfur atom.
The
heterocyclic ring may be saturated or unsaturated. Preferably, the
heterocyclic ring
is saturated. Further preferably, the organic compound contains a thiadiazole
ring
and particularly 1,3,4-thiadiazole ring. For example, a dimer of 2,5-
dimercapto-
1,3,4-thiadiazole may be used as the organic compound containing the disulfide
group.
The electrically conductive polymer in use with the organic compound
containing the
disulfide group preferably has a ~ electron conjugated structure. Examples of
such
electrically conductive polymer include polymers obtained by polymerizing
~0 thiophene, pyrrole, aniline, furan, benzene, or the like. More
specifically, examples
of the polymers include polyaniline, polypyrrole, polythiophene, and
polyacene.
These n electron conjugated electrically conductive polymers are reduced and
oxidized with a high reversibility in 0 to f 1.0 V versus Ag/AgCI electrode.
Electrically conductive polymers which are doped with anions such as iodine
exhibit
excellent properties.
The electrically conductive matrix may have a porous fibril structure. For
example,
electrically conductive polymers may have a porous fibril structure, which
depends
on the polymerization conditions. In other words, electrically conductive
polymers


CA 02326175 2000-09-26
WO 99150922 ~ PCT/EP99/01945
7
may have a form of a plurality of fibrils defining pores therebetween. The
disulfide
compound may be held in the pores formed by the fibrils. Such electrically
conductive polymer having the porous fibril structure may be obtained by
polymerization at the electrode.
Alternatively, the electrically conductive matrix may be continuous being
substantially free of pores. Such electrically conductive matrix may be
obtained by
a standard chemical polymerization reaction.
Among the ~ electron conjugated electrically conductive polymers, a polymer
represented by a formula:
-[Ar-NH)~
wherein Ar is aryl, and n is an integer is preferably used. Aryl preferably
has carbon
atoms ranging from 6 to 20, and further preferably from 6 to 10. Aryl may be
phenyl,
naphthalenyl, indenyl and the like. Polyaniline wherein aryl is phenyl is
preferred.
The matrix containing the combination of the above-mentioned disulfide
compound
and an electrically conductive polymer may be produced by a well known method
such as mixing, impregnating, or coating. For example, a fibril layer of the
electrically conductive polymer is formed on a stainless steel substrate by
electrolytic polymerization, after which a salt in the disulfide compound is
impregnated in the fibril layer, thereby obtaining a composite electrode.
Alternatively, the disulfide compound particles are dispersed in a solvent in
which
the electrically conductive polymer is dissolved, and after that, the solvent
is
removed, whereby a layer of the electrically conductive polymer is formed on
the
surface of the disulfide compound particle. Furthermore, the electrically
conductive
polymer particles obtained by the chemical polymerization or electrolytic
polymerization can be mixed with the disulfide compound particles.
As another method, the electrode material of the present invention can be
obtained
by polymerizing a monomer~capable of forming a n electron conjugated
electrically
conductive polymer in the presence of the compound containing a disulfide
group
therein and having a conformation which enables a reversible cleavage of an S-
S
bond of the disulfide group in its molecule (e.g., 1,8-disulfide naphthalene).
For
example, when aniline is subjected to the electrolytic polymerization on an
electrode
in the presence of 1,8-disulfide naphthalene, a composite film of polyaniline
and
1,8-disulfide naphthalene is formed.
Alternatively, as another method, a dimer of a compound having a mercapto
group
can be used instead of a compound having a conformation which enables a
reversible cleavage of an S-S bond in its molecule. For example, a dimer of 2-


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
8
mercapto-2-thiazoline is obtained, and a polyaniline-2-mercapto-2-thiazoline
dimer
composite film can be formed by using this dimer instead of 1,8-disulfide
naphthalene. In any of the above cases, it is preferred that the
polymerization is
conducted under the conditions that a film having a fibril structure can be
formed. In
these methods, the compound in which a mercapto group is protected is used, so
that the electrically conductive polymer can be prepared without any
inhibition. In
the composite material thus obtained, the disulfide compound and the
electrically
conductive polymer forms a composite, thereby preventing the disulfide
compound
from leaking out of the composite film into the electrolyte during its use as
a cathode
of a rechargeable battery.
In the electrode of the present invention, a conductive polymer containing a
mercapto group may be used. The conductive polymer having a mercapto group
can be obtained, for example, by (1 ) introducing a mercapto group into a n
electron
conjugated conductive polymer; or (2) electrolytic polymerization of a monomer
having a mercapto group and being capable of forming a n electron conjugated
conductive polymer.
As the n electron conjugated conductive polymer in this method (1 ), a
conductive
polymer or derivatives thereof used for the first electrode material can be
used. For
example, halogenated pyrrole is subjected to the electrolytic polymerization
to from
a thin film of polyhalopyrrole on an electrode. At this time, it is preferred
that the
polymerization is conducted in the same way as in the case of the first
electrode
material under the conditions that a thin film having a fibril structure is
formed. Then,
a halogen group is converted into a mercapto group by thiourea to form
polypyrrole
having a mercapto group. After that, a compound having a mercapto group is
reacted with the polypyrrole having a mercapto group to form polypyrrole
having a
disulfide group. As the compound having a mercapto group, the disulfide
compound
(which is a reduced form and has an SH group) used for the first electrode
material,
for example, 2,5-dimercapto- 1,3,4-thiadiazole is preferably used. The
conductive
polymer in a thin film shape having a disulfide group so obtained can be used
as a
reversible electrode.
As the monomer capable of forming a n electron conjugated conductive polymer
in
this method (2), the monomer (e.g., thiophene and pyrrole) in which a
disulfide
group is introduced and capable of forming a conductive polymer used in the
first
electrode material can be used. A conductive polymer having a having a
mercapto
group can be obtained by polymerizing this monomer. For example, a thiophene
derivative having a disulfide group can be obtained by reacting thiophene
having a
mercapto group with the disulfide compound which is a reduced form and has an
SH
group. The thiophene derivative having a disulfide group thus obtained (e.g.,
2,5-


CA 02326175 2000-09-26
WO 99150922 PCT/EP99/01945
9
dimercapto-1,3,4-thiaziazole) is used .for the first electrode. This thiophene
derivative is subjected to the electrolytic polymerization on an electrode,
whereby a
conductive polymer film having a disulfide group can be formed. It is
preferred that
the polymerization is conducted under such conditions that a film having a
fibril
structure is formed. The conductive polymer film thus formed functions as a
reversible electrode.
In the electrode of the present invention, a plurality of carbon nanotubes are
dispersed in the electrically conductive matrix. The carbon nanotubes conducts
electricity along the axial direction thereof, thereby decreasing electric
resistance of
the matrix. Typically, the carbon nanotubes has less resistance and conducts
more
electricity than the electrically conductive polymer. Moreover, the presence
of the
carbon nanotubes serving as a filler increases mechanical strength of the
matrix.
Carbon nanotubes are graphitic fibers having a microscopic tubular structure.
While
carbon nanotubes are graphitic, geometric constraints force some differences
from
pure graphite. Like graphite, carbon nanotubes are composed of parallel layers
of
carbon but in the form of a series of concentric tubes disposed about the
longitudinal axis of the fibers rather than as multi-layers of flat graphite
sheets.
Thus, because of the geometric constraints in the narrow diameter of the
carbon
nanotubes, the graphite layers cannot line up precisely with respect to the
layers
below as flat graphite sheets can.
Ideally, a carbon nanotube consists of one or more seamless cylindrical shells
of
graphitic sheets. In other words, each shell is made of sp2 (trivalent) carbon
atoms
that from a hexagonal network without any edges. A carbon nanotube can be
thought of as a tubular microcrystal of graphite. The tube is typically closed
at each
end by the introduction of pentagons in the hexagonal network. Multishell
nanotubes may have interlayer spacing of about 0.34 manometers and typical of
turbostratic graphite, in which the position of each layer relative to the
next is not
correlated. A given nanotube will be composed of shells having different
helicities.
In fact, the different degrees of helicity in each shell are necessary to
obtain the
best fit between the successive shells in a tube and minimize the interlayer
distance.
The carbon nanotubes may be catalytically prepared. The ~ process provides
aggregates uncontaminated with amorphous carbon allowing carbon nanotubes to
be fashioned into a product with only minimal processing. The carbon nanotubes
are grown by contacting catalyst particles with gaseous hydrocarbon in a
hydrogen
rich atmosphere. Their diameters may be average 7 to 12 manometers. Lengths
may be several micrometers. They are hollow tubes with wall thicknesses of 2
to 5
manometers. These walls are essentially concentric tubes of individual
graphite
layers rolled into cylinders. At intervals along the length of a fiber some of
the inner


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
layers may curve into hemispherical septa spanning the hollow interior. Near
these,
the walls may for a short distance change into nested cones. These reflect
changes
in the catalyst/carbon interface during growth of the fibril. Unlike other
catalytic
vapor grown carbon fibers they are free of less organized pyrolytic carbon on
their
5 surfaces.
Carbon nanotubes may be prepared by condensation of carbon vapor in an arc.
The carbon vapor may be produced by irradiating laser onto a carbon-nickel-
cobalt
mixture at 1200°C as reported in Science Vol. 273, July 26, 1996 page
483. They
usually have a wider distribution of diameters from single layer walls to many
tens of
10 layers. Some have only concentric cylinders (or polygonal cross sections).
Others
also have septa and nested cones. Less organized carbon is deposited at the
same
time in the form of polygons or turbostratic carbon some of which may coat the
carbon nanotubes.
The carbon nanotubes prepared by condensation of carbon vapor in an arc are
commercially available from Materials & Electrochemical Research Corporation
and
from its distributor of Science Laboratory Incorporation at Matsudo, Chiba,
Japan.
The carbon nanotubes from Materials & Electrochemical Research Corporation may
have average lengths ranging from 0.199 ~,m to 2.747 ~sm, and average
diameters
ranging from 18.5nm to 38.7nm. The carbon nanotubes contain some non-tubular
carbon particles as well. In one sample, carbon nanotubes have length of
0.84310.185 Vim, diameter of 19.613.7 nm, and an aspect ratio of 47.2111.7.
Such
carbon nanotubes may be used in the present invention.
As would be expected from their structure and similarity to graphite, carbon
nanotubes are conductive. While the conductivity of individual carbon
nanotubes is
difficult to measure, a recent attempt has yielded an estimated resistivity
value of
9.5 (14.5) m S2 cm, a resistivity slightly higher than typically measured for
graphitized carbon.
The diameter of the carbon nanotubes that are used in this invention may be
3.5 to
200 nm, and, preferably, 5 to 30 nm and their length should be at least
greater than
5 times their diameter, and preferably, 102 to 10' times their diameter.
When the diameter of the carbon nanotubes exceeds 200 nm, their effect in
providing conductivity is decreased. When it is less than 3.5 nm, the carbon
nanotubes may scatter and become difficult to handle. When the length of the
carbon nanotubes is less than 5 times their diameter, conductivity is reduced.
The aspect ratio of each of the carbon nanotubes may ordinarily be greater
than 5,
preferably, greater than 100, and, more preferably, greater than 1000.
The carbon nanotubes that are used in this invention can be obtained, for
example,
using carbon nanotubes manufactured by the method described in Japanese Patent


CA 02326175 2000-09-26
WO 99150922 PCT/EP99/01945
11
Application No. 2-503334 [1990] as the raw material. This material may be use
in
unaltered from or be subjected to chemical or physical treatment, after which
it is
subjected to pulverization treatment. The chemical or physical treatment may
be
carried out before or after the pulverization treatment.
Examples of physical or chemical treatments of the carbon nanotubes include
oxidation with nitric acid, oxidation with ozone, organic plasma treatment,
coating
with resins such as epoxy resins and treatment with coupling agents such as
organic silicon and titanium compounds. The physical treatment further
includes
providing a sheer force onto a liquid containing aggregate of carbon
nanotubes,
thereby disentangling the aggregate.
In the present invention, carbon nanotubes in the form of aggregate may be
used.
Alternatively, disentangled carbon nanotubes may be used.
When the electrolytic reduction is conducted in the presence of metal ions or
protons at the electrode made of the present invention, the S-S bond of the
disulfide
group of the electrode material is cleaved to form a sulfur-metal ion bond or
a sulfur-
proton bond. The resulting electrode is subjected to electrolytic oxidation,
and the
sulfur-metal ion bond or sulfur-proton bond returns to the S-S bond. The
electrolytic
oxidation and the electrolytic reduction involves electron transfers, which
are
facilitated by carbon nanotubes in the electrically conductive matrix.
' Examples of the metal ion include an alkali metal ion and an alkaline earth
metal
ion. In the case where the electrode made of the electrode material of the
present
invention is used as a cathode, and a lithium ion is used as the alkali metal
ion;
when an electrode made of lithium or a lithium alloy such as lithium-aluminum
is
used as an anode which supplies and captures lithium ions, and an electrolyte
which can transmit lithium ions is used, a battery having a voltage of 3 to 4
V can be
obtained. When an electrode made of a hydrogen storage alloy such as LaNiS is
used as an anode which supplies and captures protons, and an electrolyte which
can conduct protons is used, a battery having a voltage of 1 to 2 V can be
obtained.
In the combination of the disulfide compound and the n electron conjugated
electrically conductive polymer, the n electron conjugated electrically
conductive
polymer functions as an electrode catalyst for the electrolytic oxidation and
reduction of the disulfide compound. In the case of the n electron conjugated
electrically conductive polymer having a disulfide group, when the disulfide
group is
subjected to the electrolytic oxidation and reduction, the electronic
structure given
by the conjugated n electron functions as an electrode catalyst. In the case
of the
disulfide compound alone, the difference between the oxidation potential and
the
reduction potential is 1 V or more. However, in the case of using a
combination of
the ~ electron conjugated electrically conductive polymer and the disulfide


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
12
compound, or the electrically conductive polymer having a disulfide group, the
difference between the oxidation potential and the reduction potential is
reduced to
0. 1 V or less. In the disulfide compound which is combined with the ~
electron
conjugated electrically conductive polymer or which is introduced into such a
polymer, the electrode reaction is promoted and a higher current density at
room
temperature is obtained on electrolysis, i.e., on charging or discharging.
When the
electrode material of the present invention is subjected to electrolytic
oxidation, the
n electron conjugated electrically conductive polymer (a conjugated polymer
portion
in the case of the electrically conductive polymer having a disulfide group)
is
oxidized at first and the resulting oxidized form of the polymer oxidizes the
reduced
type of the disulfide compound (an SH or S-metal ion portion in the case of
the
electrically conductive polymer having a disulfide group). Thus, the oxidized
form of
the n electron conjugated polymer returns to the reduced form and an oxidized
form
of the disulfide compound is generated (i.e., a disulfide group is formed).
When the
electrolytic reduction is first conducted, the electrically conductive polymer
is
reduced and the resulting reduced form reduces the oxidized form of the
disulfide
compound. Thus, the reduced form of the n electron conjugated polymer returns
to
the oxidized form and the disulfide compound becomes a reduced form. The
introduction of the electrode catalyst into the disulfide compound electrode
is
disclosed in U.S. Pat. No. 4,833,048 or J. Electrochem. Soc., Vol. 136, pp.
2570-
2575 (1989). However, as the electrode catalyst, only the organic metallic
compound is disclosed. The effects of the electrode catalyst are not described
in
detail. As described above, the n electron conjugated polymer or the
conjugated
polymer portion has a function for promoting the movement of the electrons in
the
oxidation-reduction reaction. It functions as a catalyst in the oxidation-
reduction of
disulfide, reducing the activation energy of the reaction. In addition to
that, the n
electron conjugated polymer or -the conjugated polymer portion increases an
effective reaction area between the electrolyte and the electrodes.
The lithium battery of the present invention includes the cathode which the
aforementioned electrode serves as.
An anode of the lithium battery of the present invention is not limited. The
anode
may contain a carbon material, and the carbon material includes natural
graphite,
artificial graphite, amorphous carbon, fbrous carbon, powdery carbon,
petroleum
pitch carbon, and coal coke carbon. It is preferred that these carbon
materials are
particles or fibers having a diameter of 0.01 to 10 micrometers and a length
of from
several micrometers to several millimeters.
An anode of a lithium battery may contain aluminum or an alloy containing
aluminum. Example of the aluminum or alloys thereof includes AI, AI-Fe, AI-Si,
AI-


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
13
Zn, AI-Li, and AI-Zn-Si. It is preferred that the aluminum or alloys thereof
are flaky
powders obtained by rapid cooling, or spherical or amorphous powders obtained
by
mechanical crushing in the air or an inactive gas such as nitrogen. The
particle size
is preferably 1 ~m to 100 ~,m.
The mixing ratio of the carbon material to the aluminum or aluminum alloy may
be
0.01 to 5 parts by weight, preferably 0.05 to 0.5 parts by weight based on one
part
by weight of the aluminum or aluminum alloy.
Alternatively, the anode may be so-called rocking chair cell. Intercalated
compounds such as graphite may intercalate the lithium therebetween.
The electrolyte of the lithium secondary battery of the present invention is
not limited
as long as the electrolyte conducts lithium ions. The electrolyte may be a
liquid
electrolyte, a solid electrolyte and a gel electrolyte. Preferably, the
electrolyte is the
solid or gel electrolyte, and further preferably the electrolyte maintain a
solid state or
a gel state at temperatures ranging from -20° to 60°C.
Alternatively, a porous
separator defining pores and being made of a polymer material may be disposed
between the cathode and the anode, and the liquid electrolyte may be present
in the
pores thereof. The liquid electrolyte man contain a lithium salt dissolved
therein.
The solid electrolyte may contain a lithium salt and preferably contain a
polymer
containing the lithium salt. Examples of the salt containing lithium include
Lil, Li3N-
Lil-8203, Lil ~ H20, and Li-f3-AI203.
For example, the solid electrolyte may be a composite of polyethylene oxide
and a
lithium salt dissolved therein. In addition, the solid electrolyte may be a
poly(acrylonitrile) ~Im comprising propylene carbonate and LiC104 dissolved in
the
propylene carbonate.
The anode and the cathode may contain the component for the electrolyte. For
example, a composition for the solid electrolyte may comprise: a polyether
obtained
by adding ethylene oxide and butylene oxide to a polyamine; an ion-
exchangeable
compound having a layered crystal structure; and a lithium salt, and such
composition may be mixed added to a composition for the anode or the cathode.
The polyether can be obtained by the addition reaction of ethylene oxide and
butylene oxide with polyamine using an alkali catalyst at 100°C to
180°C under an
atmospheric pressure of 1 to 10 atm. As the polyamine which is a component of
the
above polyether, polyethylenimine, polyalkylenepolyamine or derivatives
thereof can
be used. Examples of the polyalkylenepoly- amine include diethylenctriamine,
triethylenetetramine, hexamethylenetctramine, and dipropylenetriamine. The
additional number of the total moles of ethylene oxide and butylene oxide is 2
to 150
moles per one active hydrogen of the polyamine. The molar ratio of ethylene
oxide
(EO) to butylene oxide (BO) is 90120 to 10190 (=EOIBO). The average molecular


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
14
weight of the poly ether thus obtained is in the range of 1,000 to 5,000,000.
It is
preferred that the polyether is contained in the solid electrode composition
in an
amount of 0.5 to 20% by weight. The polyether of the solid electrolyte serves
as a
surfactant so that this composition is uniformly dispersed.
Examples of the ion-exchangeable compound having a layered crystal structure
include clay minerals including silicate such as montmorillonite, hectorite,
saponite,
and smectite, phosphoric esters such as zirconium phosphate and titanium
phosphate, vanadic acid, antimonic acid, tungstic acid; or substances obtained
by
modifying these acids with organic cations such as quaternary ammonium salts
or
with organic polar compounds such as ethylene oxide and butylene oxide.
Fig. 4 is a cross section of a laminated structure used for a lithium battery.
The
structure 30 has a cathode 34, an anode 38 having an active material for
releasing
lithium ions; and an electrolyte 36 being disposed between the cathode 34 and
the
anode 38. The structure has a cathode current collector 32 contacting with the
cathode 34; and an anode current collector 40 contacting with the anode 38. In
the
present invention, the cathode 34 has an electrically conductive matrix
containing a
disulfide group, wherein an S-S bond of the disulfide group is cleaved by
electrochemical reduction and reformed by electrochemical oxidation; and a
plurality
of carbon nanotubes being dispersed in the electrically conductive matrix. The
cathode current collector 32, the cathode 34, the electrolyte 36, the anode
38, and
the anode current collector 40 have a layered structure and are laminated each
other in this order. The electrolyte 36 may have at least one of a solid
electrolyte
and a gel electrolyte.
When the lithium secondary battery of the present invention is charged, Li is
liberated from an S-Li bond of the cathode and an S-S bond is formed. On the
surface of the anode or inside the anode (when the anode component and the
electrolyte component are mixed), lithium is uniformly deposited. Since
lithium is
directly deposited from the electrolyte, impurities such as oxygen are not
likely to
contaminate. Accordingly, even when the charging and discharging are repeated,
cun-ent is not likely to concentrate, whereby any short-circuit in the battery
can be
effectively prevented. Lithium generated during charging (electrolysis) and
electrolyte are in a good contact with each other, so that the polarization
during
discharging can be decreased, and a higher current can be realized. As
described
above, when the electrolyte is mixed in the cathode andlor the anode,
especially
effective results can be obtained. In this case, it is particularly effective
that
compounds having lithium salts, polyether, and a layered crystal structure are
used
as the electrolyte.
The lithium secondary battery of the present invention can be prepared by the


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
following method also. Firstly, aggregates of carbon nanotubes are obtained by
a
conventional method.
Disentangled carbon nanotubes may be obtained by a process including the steps
of: adding a plurality of aggregates of carbon nanotubes to a liquid; and
providing
5 sheer force onto the liquid for disentangling the aggregates of carbon
nanotubes
therein.
The liquid may have a viscosity at 25°C of not less than 0.8
centipoise and
preferably not less than 1.0 centipoise since the viscose liquid facilitates
to apply
sheer force by mechanical process. The viscosity of some liquids are
summarized
10 in Table 3.
Table 3
liguid viscosity at 25°C in centipoise
15 N-methyl-2-pyrrolidone 1.67
2-propanol 1.77
methanol 0.545
The liquid may be an organic solvent or water. The organic solvent is
preferably
polar. Examples of the organic solvent includes N-methyl-2-pyrrolidone. When
water is used, preferably, water contains a surfactant. The sheer force may be
provided by a mechanical process, and the liquid containing the aggregates may
passed through a narrow gap at a high speed.
For example, a homogenizes may be used to apply the sheer force. In Fig. 1,
the
homogenizes 10 has a stator 12 which has a radially inner surface 13; and a
rotor 22
which has a radially outer surface 23. The stator 12 and the rotor 22 shares
an axis.
The radially inner surface 13 of the stator 12 and the radially outer surface
23 of the
rotor 22 define a narrow gap having an arc or circular configuration
therebetween.
A blade 26 is fixed to the rotor 22 and being disposed in the narrow gap. As
the
rotor 22 rotates, the blade 26 rotates along the narrow gap.
The stator 12 is formed of at least one hole 14 in radial directions, allowing
a liquid
passing therethrough. Similarly, the rotor 22 is formed of at least one hole
24 in
radial directions, allowing a liquid passing therethrough. Typically, the
liquid passes
through the hole 24 in radially outward directions and subsequently through
the hole
14 in radially outward directions.
When the liquid has a plurality of aggregates 16, the aggregates 16 are forced
to
pass through the narrow gap by the blade 26 so that sheer force is applied
thereonto. The aggregate 16 is disentangled gradually and becomes smaller


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
16
particles 18.
Alternatively, the ultrasonic generator may apply ultrasonic waves onto the
liquid
containing the aggregates, thereby disentangling the aggregates therein.
Preferably, a mixture containing disentangled carbon nanotubes and a liquid
medium is mixed with the organic compound containing the disulfide group and
the
electrically conductive polymer. Alternatively, the mixture containing
disentangled
carbon nanotubes and the liquid medium may be mixed with the electrically
conductive polymer containing the mercapto group. The liquid medium may be the
same as or different from the liquid used for disentangling aggregates of
carbon
nanotubes.
A battery precursor having the current collector and the cathode film
laminated
thereon can be prepared by coating the composition for the cathode film onto
the
current collector, which may be metallic foil.
The structure 30 of Fig. 4 may be made from the battery precursor. The
electrolyte
36, the anode 38 and the anode current collector 40 may be laminated onto the
battery precursor.
A plurality of the structures 30 may be laminated each other and packed in a
housing to produce a lithium battery. Alternatively, a plurality of the
structures 30
may be rolled to a generally cylindrically configuration, and then packed in a
housing.
The lithium secondary battery of the present invention can be prepared by the
following method also. Respective compositions of the cathode, the anode, and
the
electrolyte are molded into films. The composition of the cathode contains the
carbon nanotubes. The cathode film, electrolyte film, and anode film are
laminated
in this order and pressed together, thereby obtaining a unit cell. If
required,
electrically conductive foils, serving as current collectors, and leads are
attached to
the cathode and the anode of this unit cell, and the assembly is packaged,
thereby
producing a lithium secondary battery. Preferably, the electrolyte component
is
admixed in the cathode andlor the anode.
EXAMPLE
Example 1
Carbon Nanotubes
Firstly, aggregates of carbon nanotubes were disentangled. The aggregates of
carbon nanotubes were added to 1-methyl-2-pyrrolidone to give a mixture
containing 1 percent by weight of the carbon nanotubes. The mixture was added
to


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
17
a homogenizes under a trade name of ULTRA TALUX T-25 from IKA Japan
Company Limited in Nakayama-ku, Yokohama, Japan. The homogenizes applied
sheer force to the mixture, thereby disentangling the aggregate. The
homogenizes
has a structure of Fig. 1. In the homogenizes, the rotor may rotate 8,000 to
24,000
round per minute.
Secondly, we confirmed that aggregates of carbon nanotubes were disentangled
by
following procedures, which are not necessary in producing an electrode
including
the disentangled carbon nanotubes. To the liquid mixture thus obtained, which
contains one part by weight of carbon nanotubes, was added 19 parts by weight
of
polymethylmethacrylate serving as a binder and further N-methyl-2-pyrroiidone
for
dilution. The polymethylmethacrylate, which is referred to PMMA hereinafter,
has a
weight average molecular weight of 996,000 and is commercially available from
Aldrich. The liquid mixture was tasted onto a glass substrate, and the glass
substrate was placed in a vacuum oven for evaporating the solvent, thereby
producing a PMMA film containing 5 percent by weight of carbon nanotubes. We
observed the PMMA film by transmission electron microscopy. Fig. 2 is a
photograph of the result. Fibrils, which correspond to carbon nanotubes, are
disentangled and dispersed in the PMMA matrix.
As a comparative example, we did not apply sheer force to the liquid mixture
containing aggregates of the carbon nanotubes. Specifically, the liquid
mixture
containing N-methyl-2-pyrrolidone and 1 percent by weight of carbon nanotubes
was mixed by a magnetic stirrer overnight. Another PMMA film was produced in
the
same manner as mentioned above using the resultant liquid mixture, and the
PMMA
film was observed by transmission electron microscopy. Fig. 3 is a photograph
of
the result. A plurality of aggregates of the carbon nanotubes are present in
the
matrix.
Battery Precursor
1.8 gram of a powder of 2,5-dimercapto-1,3,4-thiadiazole was mixed with 1.2
gram
of polyaniline by a ball mill. To 2.5 gram of the powder mixture was added
11.1
gram of a liquid mixture containing 2 percent by weight of disentangled carbon
nanotubes in N-methyl-2-pyrrolidone, and the resultant mixture was mixed in a
mortar to produce an ink. The ink was coated onto a copper foil having a
thickness
of 35 micrometers using a doctor blade having a gap of 200 micrometers. The
copper foil was placed in a vacuum oven at 80°C for 3 hours for drying
the ink
therein, thereby producing a battery precursor having the copper foil and the
film
serving as a cathode and having a thickness of about 40 micrometers coated


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
18
thereon.
The resistivity of the film was determined by an instrument for determining
resistivity, which has a trade name of K-705RS and which is commercially
available
from Kyowa Riken. The resistivity of the film was 40 ohm per square
centimeter.
The adhesion of the film onto the copper foil was determined by a grid tape
test in
accordance with Japan Industrial Standard K 5400 8.5.2. The test provided 6 to
8
points, which indicates that the film did not adhere to the tape and that the
film
adhered to the copper foil.
Hardness of the film having a thickness of 20 micrometers onto the copper foil
was
determined by scrabbling a surface of the film by a pencil having a hardness
of 8H
in accordance with Japan Industrial Standard K 5400 8.4.1. The scrabbling
hardly
damage the surface of the film. The film was folded along with the copper
foil.
However, the film neither peel off nor crack. The result shows that the film
maintains flexibility, which is critical to manufacturing a lithium battery.
Comparative Example 1
As a comparative example, a battery precursor having the copper foil and the
film
serving as a cathode coated thereon was produced in the same manner except
that
carbon nanotubes were replaced by ketjen black, which is commercially
available
from Akzo.
The resistivity of the film was determined by the same instrument to be 50
kiloohm
per square centimeter.
The adhesion of the film was determined by the same grid tape test in
accordance
with Japan Industrial Standard K 5400 8.5.2, and the test provided 0 point,
which
indicates that the film peeled off along with the tape from the copper foil.
The scrabbling test of the film having a thickness of 55 micrometers onto the
copper
foil in accordance with Japan Industrial Standard K 5400 8.4.1 showed that a
soft
pencil having a hardness of HB damages the surface of the film. The result
shows
that the film incorporating ketjen black is much softer than the film
incorporating
carbon nanotubes.
Example 2
Lithium Secondary Battery
A lithium secondary battery having a coin configuration was produced. The
aforementioned battery precursor was cut to a disk configuration having a
diameter


CA 02326175 2000-09-26
WO 99/50922 PCT/EP99/01945
19
of 16 mm and used as the cathode.
A gel electrolyte was obtained by a method as follows. To a mixture of 14.5
gram of
propylene carbonate and 25.1 gram of ethylene carbonate was added 4.8 gram of
lithium tetrafluoroborate. A powder of 5.0 gram of a copolymer of
polyacrylonitrile
and polymethylacrylate, which was commercially available from Scientific
Polymer
Product and has a weight average molecular weight of 100,000. The mixture thus
obtained was stirred by magnetic stirrer for one day to obtain a polymeric
dispersion
having a white color. The polymeric dispersion was placed in a tray made of
stainless steel, and heated to 125 degree Celsius to obtain a colorless
dispersion.
Meanwhile, onto a glass sheet was placed a pair of TEFLON sheets with a
thickness of 0.5 mm at both ends of the glass substrate. The polymeric
dispersion,
which is colorless and flowable, was added to the glass substrate between the
TEFLON sheets. Another glass sheet is placed onto the glass sheet, and the
pair of
glass sheets were cooled to room temperature. Subsequently, the glass sheets
was
further cooled in a freezer, and then warmed back to room temperature. The gel
film
thus obtained was cut in a circular configuration having a diameter of 18 mm.
A foil made of metallic lithium was used as the anode, and the copper foil was
used
as the anode current collector.
The battery precursor, the gel electrolyte, the anode, and anode current
collector
were laminated in this order.
The lithium secondary battery having a coin configuration was subject to
repeated
cycles of discharging and charging. It turned out that the lithium battery
maintained
more than 90 percent of discharging capacity after 100 cycles of discharging
and
charging.
An electrode of the present invention has improved electric conductivity and
mechanical strength. Compared to other carbon materials, a smaller amount of
carbon nanotubes allow to maintain necessary electrical conductance and
mechanical strength of the electrode.
A battery precursor of the present invention has improved adhesion to the
current
collector.
The electrode of the present invention is suitable for a cathode of a lithium
battery
and particularly a lithium secondary battery. The electrode may be used in a
sensor
for detecting an electric potential of a medium.

Representative Drawing

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Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date Unavailable
(86) PCT Filing Date 1999-03-23
(87) PCT Publication Date 1999-10-07
(85) National Entry 2000-09-26
Examination Requested 2003-12-22
Dead Application 2008-03-25

Abandonment History

Abandonment Date Reason Reinstatement Date
2007-03-23 FAILURE TO PAY APPLICATION MAINTENANCE FEE
2007-08-21 R30(2) - Failure to Respond
2007-08-21 R29 - Failure to Respond

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $300.00 2000-09-26
Maintenance Fee - Application - New Act 2 2001-03-23 $100.00 2001-03-22
Registration of a document - section 124 $100.00 2001-07-25
Registration of a document - section 124 $100.00 2001-07-25
Registration of a document - section 124 $100.00 2001-07-25
Maintenance Fee - Application - New Act 3 2002-03-25 $100.00 2002-02-22
Maintenance Fee - Application - New Act 4 2003-03-24 $100.00 2003-03-18
Request for Examination $400.00 2003-12-22
Maintenance Fee - Application - New Act 5 2004-03-23 $200.00 2004-02-13
Maintenance Fee - Application - New Act 6 2005-03-23 $200.00 2005-03-08
Maintenance Fee - Application - New Act 7 2006-03-23 $200.00 2006-03-10
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
AXIVA GMBH
Past Owners on Record
DAVIES, BARRIE LINTON
MOKUDAI, HIDEHISA
MURATA, MAKOTO
OGURA, SHIZUO
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Description 2000-09-26 19 1,161
Abstract 2000-09-26 1 38
Cover Page 2001-01-12 1 30
Claims 2000-09-26 4 165
Correspondence 2001-01-04 1 2
Assignment 2000-09-26 3 89
PCT 2000-09-26 10 317
Assignment 2001-07-25 4 152
Prosecution-Amendment 2003-12-22 1 39
Fees 2001-03-22 1 37
Prosecution-Amendment 2007-02-21 2 84
Drawings 2000-09-26 4 488