U.S. patent application number 09/739241 was filed with the patent office on 2002-01-31 for polymer solid electrolyte.
Invention is credited to Matoba, Yasuo, Miura, Katsuhito, Sakashita, Takahiro, Shoji, Shigeru.
Application Number | 20020012849 09/739241 |
Document ID | / |
Family ID | 26522637 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020012849 |
Kind Code |
A1 |
Miura, Katsuhito ; et
al. |
January 31, 2002 |
Polymer solid electrolyte
Abstract
A polymer solid electrolyte obtained by blending (1) a polyether
copolymer having a main chain derived form ethylene oxide and an
oligooxyethylene side chain, (2) an electrolyte salt compound, and
(3) a plasticizer of an aprotic organic solvent or a derivative or
metal salt of a polyalkylene glycol having a number-average
molecular weight of 200 to 5,000 or a metal salt of the derivative
is superior in ionic conductivity and also superior in
processability, moldability and mechanical strength to a
conventional solid electrolyte. A secondary battery is constructed
by using the polymer solid electrolyte in combination with a
lithium metal negative electrode and a lithium cobaltate positive
electrode.
Inventors: |
Miura, Katsuhito; (Hyogo,
JP) ; Shoji, Shigeru; (Hyogo, JP) ; Sakashita,
Takahiro; (Osaka, JP) ; Matoba, Yasuo; (Hyogo,
JP) |
Correspondence
Address: |
Harold C. Wegner
FOLEY & LARDNER
Washington Harbour
3000 K Street, N.W., Suite 500
Washington
DC
20007-5109
US
|
Family ID: |
26522637 |
Appl. No.: |
09/739241 |
Filed: |
December 19, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09739241 |
Dec 19, 2000 |
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09051776 |
Mar 11, 1999 |
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6162563 |
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09051776 |
Mar 11, 1999 |
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PCT/JP97/02854 |
Aug 19, 1997 |
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Current U.S.
Class: |
429/317 ;
429/307; 429/313; 429/314 |
Current CPC
Class: |
H01B 1/122 20130101;
H01M 10/0565 20130101; Y02E 60/10 20130101; H01M 10/0568 20130101;
H01M 6/181 20130101; H01M 10/052 20130101; Y02E 60/13 20130101;
H01G 11/56 20130101; H01M 4/525 20130101; C08G 65/22 20130101 |
Class at
Publication: |
429/317 ;
429/307; 429/313; 429/314 |
International
Class: |
H01M 006/18; H01M
010/40 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 20, 1996 |
JP |
218575/1996 |
Sep 20, 1996 |
JP |
249358/1996 |
Claims
1. A polymer solid electrolyte comprising: (1) an optionally
crosslinked polyether copolymer having a number-average molecular
weight of 10,000 to 2,000,000 and comprising: (A) 1 to 99% by mol
of a repeating unit derived from a monomer represented by the
formula (I): 26 wherein R.sup.1 is a group selected from an alkyl
group having 1 to 12 carbon atoms, an alkenyl group having 2 to 8
carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an
aryl group having 6 to 14 carbon atoms, an aralkyl group having 7
to 12 carbon atom and a tetrahydropyranyl group; and n is a numeral
of 1 to 12; (B) 99 to 1% by mol of a repeating unit derived from a
monomer represented by the formula (II): 27 ; and (C) 0 to 15% by
mol of a repeating unit derived from a monomer having one epoxy
group and at least one reactive functional group; (2) an
electrolyte salt compound; and (3) a plasticizer selected from the
group consisting of an aprotic organic solvent, and a derivative or
metal salt of a straight-chain or branched polyalkylene glycol
having a number-average molecular weight of 200 to 5,000 or a metal
salt of the derivative.
2. The polymer solid electrolyte according to claim 1, wherein the
glass transition temperature and fusion heat of the polyether
copolymer measured by a differential scanning calorimeter (DSC) are
not more than -60.degree. C. and not more than 90 J/g,
respectively.
3. The polymer solid electrolyte according to claim 1, the reactive
functional group in the constituent unit (C) is (a) a reactive
silicon group, (b) an epoxy group, (c) an ethylenically unsaturated
group or (d) a halogen atom.
4. The polymer solid electrolyte according to claim 1, wherein the
repeating unit (C) is derived from a monomer of the formula (III-1)
or (III-2): 28wherein R.sup.2 and R.sup.3 represent a group having
a reactive functional group.
5. The polymer solid electrolyte according to claim 1, wherein the
monomer having a reactive silicon group, which constitutes the
repeating unit (C), is represented by the formula (III-a-1-1),
(III-a-1-2) or (III-a-2-1): 29wherein R.sup.4, R.sup.5 and R.sup.6
may be the same or different, and at least one of them represents
an alkoxy group and the remainder represents an alkyl group; and m
represents 1 to 6.
6. The polymer solid electrolyte according to claim 1, wherein the
monomer having a reactive silicon group, which constitutes the
repeating unit (C), is 3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropylmethyldimetho- xysilane,
4-(1,2-epoxy)butyltrimethoxysilane, 5-(1,2-epoxy)pentyltrimethox-
ysilane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
7. The polymer solid electrolyte according to claim 1, wherein the
monomer having two epoxy groups, which constitutes the repeating
unit (C), is represented by the formula (III-b): 30wherein R.sup.7
is a divalent organic group.
8. The polymer solid electrolyte according to claim 7, wherein
R.sup.7 in the formula (III-b)
is--CH.sub.2--O--(CHA.sup.1--CHA.sup.2--O).sub.m--CH.-
sub.2--,--(CH.sub.2).sub.m--,or--CH.sub.2O--Ph--OCH.sub.2--wherein
A.sup.1 and A.sup.2 represent hydrogen or a methyl group; Ph
represents a phenylene group; and m represents a numeral of 0 to
12.
9. The polymer solid electrolyte according to claim 1, wherein the
monomer having two epoxy groups, which constitutes the repeating
unit (C), is 2,3-epoxypropyl-2',3'-epoxy-2'-methyl propyl ether or
ethylene glycol-2,3-epoxypropyl-2',3'-epoxy-2'-methyl propyl
ether.
10. The polymer solid electrolyte according to claim 1, wherein the
monomer having an ethylenically unsaturated group, which
constitutes the repeating unit (C), is represented by the formula
(III-c): 31wherein R.sup.8 is a group having an ethylenically
unsaturated group.
11. The polymer solid electrolyte according to claim 1, wherein the
monomer having an ethylenically unsaturated group, which
constitutes the repeating unit (C), is allyl glycidyl ether,
4-vinylcyclohexyl glycidyl ether, .alpha.-terpinyl glycidyl ether,
cyclohexenylmethyl glycidyl ether, p-vinylbenzyl glycidyl ether,
allylphenyl glycidyl ether, vinyl glycidyl ether,
3,4-epoxy-1-butene, 3,4-epoxy-1-pentene, 4,5-epoxy-2-pentene,
1,2-epoxy-5,9-cyclododecadiene, 3,4-epoxy-1-vinylcyclohexene,
1,2-epoxy-5-cyclooctene, glycidyl acrylate, glycidyl methacrylate,
glycidyl sorbate, glycidyl cinnamate, glycidyl crotonate,
glycidyl-4-hexenoate, oligoethylene glycol glycidyl ether acrylate
having 1 to 12 oxyethylene chains, oligoethylene glycol glycidyl
ether methacrylate having 1 to 12 oxyethylene chains, oligoethylene
glycol allyl glycidyl ether having 1 to 12 oxyethylene chains, or
32(n=1-12).
12. The polymer solid electrolyte according to claim 1, wherein the
monomer having a halogen atom, which constitutes the repeating unit
(C), is represented by the formula (III-d): 33wherein R.sup.9 is a
group having at least one halogen atom.
13. The polymer solid electrolyte according to claim 1, wherein the
monomer having a halogen atom is 34wherein X represents a bromine
atom (Br) or an iodine atom (I).
14. The polymer solid electrolyte according to claim 1, wherein the
polyether copolymer comprises 3 to 99% by mol of the repeating unit
(A), 95 to 1% by mol of the repeating unit (B) and 0 to 5% by mol
of the repeating unit (C).
15. The polymer solid electrolyte according to claim 1, wherein the
electrolyte salt compound is a compound comprising a cation
selected from a metal cation, an ammonium ion, an amidinium ion and
a guanidium ion, and an anion selected from a chlorine ion, a
bromine ion, a iodine ion, a perchlorate ion, a thiocyanate ion, a
tetrafluoroborate ion, a nitrate ion, AsF.sub.6.sup.-,
PF.sub.6.sup.-, a stearylsulfonate ion, an octylsulfonate ion, a
dodecylbenzenesulfonate ion, a naphthalenesulfonate ion, a
dodecylnaphthalenesulfonate ion, a 7,7,8,8-tetracyano-p-quinodimet-
hane ion, X.sup.1SO.sub.3.sup.-,
(X.sup.1SO.sub.2)(X.sup.2SO.sub.2)N.sup.-- , (X.sup.1SO.sub.2)
(X.sup.2SO.sub.2) (X.sup.3SO.sub.2)C.sup.- and (X.sup.1SO.sub.2)
(X.sup.2SO.sub.2) YC.sup.- (wherein X.sup.1, X.sup.2, X.sup.3 and Y
respectively represent an electron attractive group).
16. The polymer solid electrolyte according to claim 15, wherein
X.sup.1, X.sup.2 and X.sup.3 independently represent a
perfluoroalkyl having 1 to 6 carbon atoms or a perfluoroaryl group
and Y represents a nitro group, a nitroso group, a carbonyl group,
a carboxyl group or a cyano group.
17. The polymer solid electrolyte according to claim 15, wherein
the metal cation is a cation of a metal selected from Li, Na, K,
Rb, Cs, Mg, Ca and Ba metals.
18. The polymer solid electrolyte according to claim 15, wherein
the metal cation is a cation of a transition metal.
19. The polymer solid electrolyte according to claim 15, wherein
the metal cation is a cation of a metal selected from Mn, Fe, Co,
Ni, Cu, Zn and Ag metals.
20. The polymer solid electrolyte according to claim 1, wherein the
formulation ratio of the electrolyte salt compound to the polyether
copolymer is so that a value of a molar ratio of the number of
moles of the electrolyte salt compound to the total number of moles
of oxyethylene units in the copolymer is from 0.0001 to 5.
21. The polymer solid electrolyte according to claim 1, wherein the
aprotic organic solvent is an aprotic organic solvent selected from
ethers or esters.
22. The polymer solid electrolyte according to claim 1, wherein the
aprotic organic solvent is an organic solvent selected from
propylene carbonate, .gamma.-butyrolactone, butylene carbonate and
3-methyl-2-oxazolidone.
23. The polymer solid electrolyte according to claim 1, wherein the
aprotic organic solvent is an organic solvent selected from
triethylene glycol dimethyl ether, triethylene glycol diethyl
ether, tetraethylene glycol dimethyl ether and tetraethylene glycol
diethyl ether.
24. The polymer solid electrolyte according to claim 1, wherein the
number-average molecular weight of the polyalkylene glycol is from
200 to 2000.
25. The polymer solid electrolyte according to claim 1, wherein the
polyalkylene glycol is polyethylene glycol or polypropylene
glycol.
26. The polymer solid electrolyte according to claim 1, wherein the
derivative of the polyalkylene glycol is an ether derivative or an
ester derivative.
27. The polymer solid electrolyte according to claim 26, wherein
the ether derivative of the polyalkylene glycol is any one of
polyethylene glycol dimethyl ether, polyethylene glycol diethyl
ether and polyethylene glycol diallyl ether.
28. The polymer solid electrolyte according to claim 26, wherein
the ester derivative of the polyalkylene glycol is any one of
polyethylene glycol dimethacrylate ester, polyethylene glycol
diacrylate ester and polyethylene glycol acetate ester.
29. The polymer solid electrolyte according to claim 1, wherein the
metal salt of the polyalkylene glycol is any one of a sodium salt,
a lithium salt and a dialkylaluminum salt.
30. The polymer solid electrolyte according to claim 1, wherein the
metal salt of the polyalkylene glycol is any one of a lithium salt
of polyethylene glycol and a dialkylaluminum salt of polyethylene
glycol.
31. The polymer solid electrolyte according to claim 1, wherein the
metal salt of the polyalkylene glycol is any one of a lithium salt
of polyethylene glycol monomethyl ether, a lithium salt of
polyethylene glycol monoethyl ether and a lithium salt of
polyethylene glycol monoallyl ether.
32. The polymer solid electrolyte according to claim 1, wherein the
metal salt of the polyalkylene glycol derivative is any one of a
dioctylaluminum salt of polyethylene glycol monomethyl ether, a
dioctylaluminum salt of polyethylene glycol monoethyl ether and a
dioctylaluminum salt of polyethylene glycol monoallyl ether.
33. The polymer solid electrolyte according to claim 1, wherein the
amount of the plasticizer is from 1 to 2,000 parts by weight based
on 100 parts by weight of the polyether copolymer.
34. A battery comprising the polymer solid electrolyte of claim 1,
a positive electrode and a negative electrode.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a polymer solid electrolyte
(solid polyelectrolyte), more particularly to a polymer solid
electrolyte which is suitable as a material for electrochemical
device (e.g. battery, capacitor, sensor).
RELATED ART
[0002] As an electrolyte constituting an electrochemical device
such as battery, capacitor and sensor, those in the form of a
solution or a paste have hitherto been used in view of the ionic
conductivity. However, the following problems are pointed out. That
is, there is a fear of damage of the device arising due to liquid
leakage, and subminiaturization and thinning of the device are
limited because a separator to be impregnated with an electrolyte
liquid is required. To the contrary, a solid electrolyte such as an
inorganic crystalline substance, inorganic glass and an organic
polymer substance is suggested. The organic polymer substance is
generally superior in processability and moldability and the
resulting solid electrolyte has good flexibility and bending
processability and, furthermore, the design freedom of the device
to be applied becomes high and, therefore, the development of the
organic polymer substance is expected. However, the organic polymer
substance is inferior in ionic conductivity to other materials at
present.
[0003] For example, a trial of containing a specific alkaline metal
salt in a mixture of an epichlorohydrin rubber and a low-molecular
weight polyethylene glycol derivative and applying the resultant to
a polymer solid electrolyte is suggested in Japanese Patent Kokai
Publication No. 235957/1990 filed by the present applicant, but a
practically sufficient conductivity value is not still to be
obtained.
[0004] Furthermore, a polymer solid electrolyte prepared by
crosslinking a polymer compound having a number-average molecular
weight of 1,000 to 20,000 described in Japanese Patent Kokai
Publication Nos. 47833/1991 and 68064/1992 shows a comparatively
good ionic conductivity within the practical temperature range, but
those having more excellent mechanical characteristics and ionic
conductivity are required.
SUMMARY OF THE INVENTION
[0005] An object of the present invention provides a solid
electrolyte which is superior in mechanical properties and ionic
conductivity.
[0006] The present invention provides a polymer solid electrolyte
(solid polyelectrolyte) comprising:
[0007] (1) an optionally crosslinked polyether copolymer having a
number-average molecular weight of 10,000 to 2,000,000 and
comprising:
[0008] (A) 1 to 99% by mol of a repeating unit derived from a
monomer represented by the formula (I): 1
[0009] wherein R.sup.1 is a group selected from an alkyl group
having 1 to 12 carbon atoms, an alkenyl group having 2 to 8 carbon
atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group
having 6 to 14 carbon atoms, an aralkyl group having 7 to 12 carbon
atom and a tetrahydropyranyl group; and n is a numeral of 1 to
12;
[0010] (B) 99 to 1% by mol of a repeating unit derived from a
monomer represented by the formula (II): 2
[0011] ; and
[0012] (C) 0 to 15% by mol of a repeating unit derived from a
monomer having one epoxy group and at least one reactive functional
group;
[0013] (2) an electrolyte salt compound; and
[0014] (3) a plasticizer selected from the group consisting of an
aprotic organic solvent, and a derivative or metal salt of a
straight-chain or branched polyalkylene glycol having a
number-average molecular weight of 200 to 5,000 or a metal salt of
the derivative.
[0015] The present invention also provides a battery using the
above polymer solid electrolyte.
[0016] The crosslinked material of the polyether copolymer is used
when the dimensional stability at high temperature is required.
[0017] When the plasticizer is blended, the crystallization of the
polymer is inhibited and the glass transition temperature is
lowered and a large amount of an amorphous phase is formed even at
low temperature so that the ionic conductivity is improved. It has
been found that, when the polymer solid electrolyte of the present
invention is used, a high-performance battery having small internal
resistance can be obtained. The polymer solid electrolyte of the
present invention may be in the gel form. The term "gel" used
herein means a polymer swelled with a solvent.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The repeating unit (C) may be derived from a monomer of the
formula 3
[0019] wherein R.sup.2 and R.sup.3 represent a group having a
reactive functional group-containing group.
[0020] The copolymer used in the present invention comprises (A) a
repeating unit derived from a monomer of the formula (I): 4
[0021] wherein R.sup.1 is a group selected from an alkyl group
having 1 to 12 carbon atoms, an alkenyl group having 2 to 8 carbon
atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group
having 6 to 14 carbon atoms, an aralkyl group having 7 to 12 carbon
atoms and a tetrahydropyranyl group and
[0022] (B) a repeating unit derived from a monomer of the formula
(II):
CH.sub.2--CH.sub.2--O.paren close-st. (II')
[0023] The copolymer further comprises (C) a repeating unit derived
from a monomer having one epoxy group and at least one reactive
functional group, if necessary.
[0024] The repeating unit (C) derived from the monomer of the
formula (III-1) or (III-2) is represented by the formula (III'-1)
or (III'-2): 5
[0025] wherein R.sup.2 and R.sup.3 represent a reactive functional
group-containing group.
[0026] The reactive functional group in the repeating unit (C) is
preferably (a) a reactive silicon group, (b) an epoxy group, (c) an
ethylenically unsaturated group, or (d) a halogen atom.
[0027] The polymerization method for the polyether copolymer of the
present invention, which may have a crosslinkable side chain, is
the same as that described in Japanese Patent Kokai Publication
Nos. 154736/1988 and 169823/1987.
[0028] The polymerization reaction can be conducted as follows.
That is, the polyether copolymer can be obtained by reacting the
respective monomers at the reaction temperature of 10 to 80.degree.
C. under stirring, using a catalyst mainly composed of an
organoaluminum, a catalyst mainly composed of an organozinc, an
organotin-phosphate ester condensate catalyst, etc. as a ring
opening catalyst in the presence or absence of a solvent. The
organotin-phosphate ester condensate catalyst is particularly
preferable in view of the polymerization degree, or properties of
the resulting copolymer. In the polymerization reaction, the
reactive functional group does not react so that a copolymer having
the reaction functional group is obtained.
[0029] In the polyether copolymer of the present invention, the
content of the repeating unit (A) is from 1 to 99% by mol, e.g.
from 3 to 99% by mol, particularly from 5 to 90% by mol; the
content of the repeating unit (B) is from 99 to 1% by mol, e.g.
from 95 to 1% by mol, particularly from 90 to 5% by mol; and the
content of the repeating unit (C) is from 0 to 15% by mol, e.g.
from 0 to 10% by mol, preferably from 0 to 5% by mol, particularly
from 0.01 to 5% by mol. When the content of the repeating unit (B)
exceeds 99% by mol, an increase in glass transition temperature and
crystallization of the oxyethylene chain arise, which results in
drastic deterioration of the ionic conductivity of the solid
electrolyte. It is generally known that the ionic conductivity is
improved by the decrease of crystallizability of polyethylene
oxide. It has been found that, in case of the polyether copolymer
of the present invention, the effect for improvement of the ionic
conductivity is remarkably large.
[0030] The glass transition temperature and fusion heat of the
polyether copolymer are measured by a differential scanning
calorimeter (DSC). In the present invention, the glass transition
temperature of the polyether copolymer is preferably not more than
-60.degree. C., preferably not more than -63.degree. C., e.g. not
more than -65.degree. C. The fusion heat of the polyether copolymer
is preferably not more than 90 J/g, e.g. not more than 70 J/g,
specifically not more than 60 J/g, particularly not more than 50
J/g.
[0031] The polyether copolymer may be any copolymer such as a block
copolymer and a random copolymer, but the random copolymer is
preferable because the effect for reduction of the
crystallizability of polyethylene oxide is large. The polyether
copolymer of the present invention is a polyether copolymer having
an oligooxyethylene side chain and, if necessary, a side chain
containing a crosslinkable reactive functional group. The polyether
copolymer of the present invention is a copolymer formed from two
or more monomers.
[0032] The monomer having a reactive silicon group, which
constitutes the repeating unit (C), is preferably represented by
the formula (III-a--1): 6
[0033] wherein R.sup.2 is a reactive silicon-containing group, or
the formula (III-a-2): 7
[0034] wherein R.sup.3 is a reactive silicon-containing group.
[0035] The reactive silicon group-containing monomer represented by
the formula (III-a-1) is preferably a compound represented by the
formula (III-a-1-1) or (II-a-1-2). 8
[0036] The reactive silicon group-containing monomer represented by
the formula (III-a-2) is preferably a compound represented by the
formula (III-a-2-1). 9
[0037] In the formulas (III-a-1-1), (III-a-1-2) and (III-a-2-1),
R.sup.4, R.sup.5 and R.sup.6 may be the same or different, and at
least one of them represents an alkoxy group and the remainder
represents an alkyl group; and m represents 1 to
[0038] Examples of the monomer represented by the formula
(III-a-1-1) include 1-glycidoxymethyltrimethoxysilane,
1-glycidoxymethylmethyldimetho- xysilane,
2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethylmethyldimethox-
ysilane, 3-glycidoxypropylmethyldimethoxysilane,
3-glycidoxypropyltrimetho- xysilane,
4-glycidoxybutylmethyldimethoxysilane, 4-glycidoxybutylmethyltri-
methoxysilane, 6-glycidoxyhexylmethyldimethoxysilane and
6-glycidoxyhexylmethyltrimethoxy-silane.
[0039] Examples of the monomer represented by the formula
(III-a-1-2) include 3-(1,2-epoxy)propyltrimethoxysilane,
3-(1,2-epoxy)propylmethyldim- ethoxy-silane,
3-(1,2-epoxy)propyldimethylmethoxysilane, 4-(1,2-epoxy)
butyl-trimethoxysilane, 4-(1,2-epoxy)butylmethylditrimethoxysilane,
5-(1,2-epoxy)pentyltrimethoxysilane,
5-(1,2-epoxy)pentylmethyldimethoxysi- lane,
6-(1,2-epoxy)hexyltrimethoxysilane and
6-(1,2-epoxy)hexylmethyldimet- hoxy-silane.
[0040] Examples of the monomer represented by the formula
(III-a-2-1) include 1-(3,4-epoxycyclohexyl)methyltrimethoxysilane,
1-(3,4-epoxycyclohexyl) methylmethyldimethoxysilane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
2-(3,4-epoxycyclohexyl)ethy- lmethyldimethoxys
3-(3,4-epoxycyclohexyl)propyltrimethoxysilane,
3-(3,4-epoxycyclohexyl)propylmethyldimethoxysilane,
4-(3,4-epoxycyclohexyl)butyltrimethoxysilane and
4-(3,4-epoxycyclohexyl) butylmethylditrimethoxysilane.
[0041] Among them, 3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropyl-methyidimethoxysilane,
4-(1,2-epoxy)butyltrimethoxysila- ne,
5-(1,2-epoxy)pentyltrimethoxysilane and
2-(3,4-epoxycyclohexyl)ethyltr- imethoxy-silane are particularly
preferable.
[0042] The monomer having two epoxy groups, which constitutes the
repeating unit (C), is preferably represented by the formula
(III-b): 10
[0043] wherein R.sup.7 is a divalent organic group. R.sup.7 is
preferably an organic group consisting of elements selected from
hydrogen, carbon and oxygen.
[0044] It is preferable that the group R.sup.7 in the formula
(III-b) is
--CH.sub.2--O--(CHA.sup.1--CHA.sup.2--O).sub.m--CH.sub.2--,
[0045] or
--(CH.sub.2).sub.m--,
[0046] or
--CH.sub.2O--Ph--OCH.sub.2--
[0047] wherein A.sup.1 and A.sup.2 represent hydrogen or a methyl
group; Ph represents a phenylene group; and m represents a numeral
of 0 to 12.
[0048] The monomer having two epoxy groups is preferably a compound
represented by the formula (III-b-1), (III-b-2) or (III-b-3):
11
[0049] In the formulas (III-b-1), (III-b-2) and (III-b-3), A.sup.1
and A.sup.2 represent hydrogen or a methyl group; and m represents
a numeral of 0 to 12.
[0050] Examples of the monomer represented by the formula (III-b-1)
include 2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether,
ethyleneglycol-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether
and diethyleneglycol-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl
ether. Examples of the monomer represented by the formula (III-b-2)
include 2-methyl-1,2,3,4-diepoxybutane,
2-methyl-1,2,4,5-diepoxypentane and 2-methyl-1,2,5,6-diepoxyhexane.
Examples of the monomer represented by the formula (III-b-3)
include hydroquinone-2,3-epoxypropyl-2',3'-epoxy-2'- -methylpropyl
ether and catechol-2,3-epoxypropyl-2',3'-epoxy-2'-methylprop- yl
ether.
[0051] Among them, 2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl
ether and
ethyleneglycol-2,3-epoxypropyl-2',3'-epoxy-2'-methylpropyl ether
are particularly preferable.
[0052] The monomer having an ethylenically unsaturated group, which
constitutes the repeating unit (C), is represented by the formula
(III-c): 12
[0053] wherein R.sup.8 is a group having an ethylenically
unsaturated group.
[0054] As the ethylenically unsaturated group-containing monomer,
there can be used allyl glycidyl ether, 4-vinylcyclohexyl glycidyl
ether, .alpha.-terpinyl glycidyl ether, cyclohexenylmethyl glycidyl
ether, p-vinylbenzyl glycidyl ether, allylphenyl glycidyl ether,
vinyl glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-1-pentene,
4,5-epoxy-2-pentene, 1,2-epoxy-5,9-cyclododecadiene,
3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5-cyclooctene, glycidyl
acrylate, glycidyl methacrylate, glycidyl sorbate, glycidyl
cinnamate, glycidyl crotonate, glycidyl-4-hexenoate, oligoethylene
glycol glycidyl ether acrylate having 1 to 12 oxyethylene chains,
oligoethylene glycol glycidyl ether methacrylate having 1 to 12
oxyethylene chains, oligoethylene glycol allyl glycidyl ether
having 1 to 12 oxyethylene chains or 13
[0055] (n=1-12). Preferable examples thereof include allyl glycidyl
ether, glycidyl acrylate and glycidyl methacrylate.
[0056] The monomer (C) having a halogen atom is preferably
represented by the formula (III-d): 14
[0057] wherein R.sup.9 is a group having at least one halogen
atom.
[0058] Examples of the monomer having a halogen atom include:
15
[0059] wherein X is a halogen atom, particularly a bromine atom
(Br) or an iodine atom (I).
[0060] The polymerization degree n of the oxyethylene unit of the
side chain portion in the monomer (I) constituting the repeating
unit (A), is preferably from 1 to 12, e.g. from 1 to 6. When the
polymerization degree n exceeds 12, the ionic conductivity of the
resulting polymer solid electrolyte is deteriorated unfavorably. In
the monomer (I), R.sup.1 may be a methyl group, an ethyl group, a
propyl group, a butyl group, a pentyl group, a hexyl group, an
allyl group or a cyclohexyl group.
[0061] The number-average molecular weight of the polyether
copolymer is within the range from 10,000 to 2,000,000, e.g. from
50,000 to 2,000,000, preferably from 100,000 to 2,000,000, so as to
obtain excellent processability, moldability, mechanical strength
and flexibility. When the number-average molecular weight is
smaller than 10,000, it is necessary to increase the crosslink
density so as to maintain the mechanical strength or to prevent
from flowing at high temperature, which results in deterioration of
ionic conductivity of the resulting polymer solid electrolyte. On
the other hand, when it exceeds 2,000,000, the processability and
moldability become insufficient.
[0062] In the crosslinking of the copolymer wherein the reactive
functional group is a reactive silicon group, the crosslinking can
be conducted by the reaction between the reactive silicon group and
water. In order to increase the reactivity, there may be used, as a
catalyst, organometal compounds, for example, tin compounds such as
dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin
octylate and dibutyltin acetylacetonate; titanium compounds such as
tetrabutyl titanate and tetrapropyl titanate; aluminum compounds
such as aluminum trisacetyl acetonate, aluminum trisethyl
acetoacetate and diisopropoxyaluminum ethylacetoacetate; or amine
compounds such as butylamine, octylamine, laurylamine,
dibutylamine, monoethanolamine, diethanolamine, triethanolamine,
diethylenetriamine, trietylenetetraamine, cyclohexylamine,
benzylamine, diethylaminopropylamine, guanine and
diphenylguanine.
[0063] As the crosslinking method of the copolymer wherein the
reactive functional group is an epoxy group, polyamines, acid
anhydrides and the like are used.
[0064] Examples of the polyamines include aliphatic polyamines such
as diethylenetriamine, dipropylenetriamine, triethylenetetramine,
tetraethylene-pentamine, dimethylaminopropylamine,
diethylaminopropylamine, dibutyl-aminopropylamine,
hexamethylenediamine, N-aminoethylpiperazine,
bis-aminopropylpiperazine, trimethylhexamethylenediamine and
dihydrazide isophthalate; and aromatic polyamines such as
4,4'-diaminodiphenyl ether, diaminodiphenyl sulfone,
m-phenylenediamine, 2,4-toluylenediamine, m-toluylenediamine,
o-toluylenediamine and xylylenediamine. The amount of the polyamine
varies depending on the type of the polyamine, but is normally
within the range from 0.1 to 10% by weight based on the whole
composition excluding a plasticizer.
[0065] Examples of the acid anhydrides includes maleic anhydride,
dodecenylsuccinic anhydride, chlorendic anhydride, phthalic
anhydride, pyromellitic anhydride, hexahydrophthalic anhydride,
methylhexahydrophthalic anhydride, tetramethylenemaleic anhydride,
tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride
and trimellitic anhydride. The amount of the acid anhydrides varies
depending on the type of the acid anhydride, but is normally within
the range from 0.1 to 10% by weight based on the whole composition
excluding a plasticizer. In the crosslinking, an accelerator can be
used. In the crosslinking reaction of polyamines, the accelerator
includes phenol, cresol, resorcin, pyrogallol, nonyl phenol,
2,4,6-tris(dimethylaminomethy- l)phenol. In the crosslinking
reaction of the acid anhydride, the accelerator includes
benzyldimethylamine, 2,4,6-tris(dimethylamino-methyl- )phenol,
2-(dimethylaminoethyl)phenol, dimethylaniline and
2-ethyl-4-methylimidazol. The amount of the accelerator varies
depending on the type of the accelerator, but is normally within
the range from 0.1 to 10% by weight based on the crosslinking
agent.
[0066] In the crosslinking method used in the copolymer, when a
reactive functional group is the ethylenically unsaturated group, a
radical initiator such as an organic peroxide and an azo compound,
or active energy ray such as ultraviolet ray and electron ray can
be used. It is also possible to use a crosslinking agent having
silicon hydride.
[0067] As the organic peroxide, there can be used those which are
normally used for the crosslinking, such as ketone peroxide, peroxy
ketal, hydro-peroxide, dialkyl peroxide, diacyl peroxide, peroxy
ester and the like. Specific examples thereof include methyl ethyl
ketone peroxide, cyclohexanone peroxide,
1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane- ,
2,2-bis(t-butyl-peroxy)octane,
n-butyl-4,4-bis(t-butylperoxy)valerate, t-butylhydroperoxide,
cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydr- operoxide,
di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide,
.alpha.,.alpha.'-bis(t-butylperoxy-m-isopropyl) benzene,
2,5-dimethyl-2,5-di(t-butylperoxy)hexane,
2,5-dimethyl-2,5-di(t-butylpero- xy)hexane, benzoylperoxide and
t-butylperoxyisopropyl-carbonate. The amount of the organic
peroxide varies depending on the type of the organic peroxide, but
is normally within the range from 0.1 to 10% by weight based on the
whole composition excluding a plasticizer.
[0068] As the azo compound, there can be used those which are
normally used in the crosslinking, such as azonitrile compound,
azoamide compound, azoamidine compound and the like. Specific
examples thereof include 2,2-azobisisobutyronitrile,
2,2'-azobis(2-methylbutyronitrile),
2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile),
2,2'-azobis(2,4-dimethy- lvaleronitrile),
1,1'-azobis(cyclohexane-1-carbonitrile),
2-(carbamoylazo)isobutyronitrile,
2-phenylazo-4-methoxy-2,4-dimethyl-vale- ronitrile,
2,2-azobis(2-methyl-N-phenylpropionamidine)dihydrochloride,
2,2'-azobis[N-(4-chlorophenyl)-2-methylpropionamidine]dihydrochloride,
2,2'-azobis[N-hydroxyphenyl-2-methylpropionamidine]dihydrochloride,
2,2'-azobis[2-methyl-N-(phenylmethyl)propionamidine]dihydrochloride,
2,2'-azobis[2-methyl-N-(2-propenyl)propionamidine]dihydrochloride,
2,2'-azobis(2-methyl-propionamidine)dihydrochloride,
2,2'-azobis[N-(2-hydroxyethyl)-2-methyl-propionamidine]dihydrochloride,
2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride,
2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihyrochloride,
2,2'-azobis[2-(4,5,6,7-tetrahydro-1
H-1,3-diazepin-2-yl)propane]dihydroch- loride,
2,2'-azobis[2-(3,4,5,6-tetrahydropyrimidin-2-yl)propane]dihydrochl-
oride,
2,2'-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl)propane]d-
ihydrochloride, 2,2'-azobis{2-[1
-(2-hydroxyethyl)-2-imidazolin-2-yl]propa- ne}dihydrochloride,
2,2'-azobis[2-(2-imidazolin-2-yl)propane],
2,2'-azobis{2-methyl-N-[1,1-bis(hydroxyethyl]propionamide},
2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide),
2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide],
2,2'-azobis(2-methylpropionamide)dihydrate,
2,2'-azobis(2,4,4-trimethylpe- ntane),
2,2'-azobis(2-methylpropane), 2,2'-azobisisobutyrate,
4,4'-azobis(4-cyanovalerate) and
2,2'-azobis[2-(hydroxy-methyl)propionitr- ile]. The amount of the
azo compound varies depending on the type of the azo compound, but
is normally within the range from 0.1 to 10% by weight based on the
whole composition excluding a plasticizer.
[0069] In the crosslinking due to radiation of activated energy ray
such as ultraviolet ray, glycidyl acrylate ether, glycidyl
methacrylate ether and glycidyl cinnamate ether are particularly
preferable among the monomer component represented by the formula
(III-c). Furthermore, as an auxiliary sensitizer, there can be
optionally used acetophenones such as diethoxyacetophenone,
2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal,
1-(4-isopropyl-phenyl)-2-hydroxy-2-methylpropan-1-on- e,
4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone,
2,2-dimethoxy-1,2-diphenylethan-1-one,
1-hydroxy-cyclohexyl-phenylketone and
2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one; benzoin
ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether,
benzoin isopropyl ether and benzoin isobutyl ether; benzophenones
such as benzophenone, methyl o-benzoylbenzoate,
4-phenylbenzophenone, hydroxybenzophenone,
4-benzoyl-4'-methyl-diphenyl sulfide, alkylated benzophenone,
3,3',4,4'-tetra(t-butylperoxycarbonyl)benzo-phenone,
4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzene-methanamin-
ium bromide and (4-benzoylbenzyl)trimethylammonium chloride;
thioxanthones such as 2-isopropyl-thioxanthone,
2,4-dimethylthioxanthone, 2,4-diethylthioxanthone,
2,4-dichloro-thioxanthone; azides such as azidopyrene,
3-sulfonylazido-benzoic acid, 4-sulfonylazidobenzoic acid,
2,6-bis(4'-azidobenzal)cyclohexanone-2,2'-disulfonic acid (sodium
salt), p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoinic
acid, p-azidobenzalacetophenone, p-azidobenzalacetone,
4,4'-diazidochalcone, 1,3-bis(4'-azidobenzal)acetone,
2,6-bis(4'-azidobenzal) cyclohexanone, 2,6-bis(4-azidobenzal)
4-methylcyclohexanone, 4,4'-diazidostilbene-2,2'-d- isulfonic acid,
1,3-bis(4'-azidobenzal)-2-propanone-2'-sulfonic acid and
1,3-bis(4'-azidocinnacylidene)-2-propanone.
[0070] As an auxiliary crosslinking agent, there can be optionally
used ethylene glycol diacrylate, ethylene glycol dimethacrylate,
oligoethylene glycol diacrylate, oligoethylene glycol
dimethacrylate, propylene glycol diacrylate, propylene glycol
dimethacrylate, oligopropylene glycol diacrylate, oligopropylene
glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene
glycol diacrylate, 1,3-glycerol dimethacrylate,
1,1,1-trimethylol-propane dimethacrylate, 1,1,1-trimethylolethane
diacrylate, pentaerythritol-trimethacrylate,
1,2,6-hexanetriacrylate, sorbitol pentamethacrylate,
methylenebisacrylamide, methylenebismethacrylamide divinyl benzene,
vinyl methacrylate, vinyl crotonate, vinyl acrylate, vinyl
acetylene, trivinyl benzene, triallyl cyanyl sulfide, divinyl
ether, divinyl sulfo ether, diallyl phthalate, glycerol trivinyl
ether, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl
fumarate, diallyl itaconate, methyl methacrylate, butyl acrylate,
ethyl acrylate, 2-ethylhexyl acrylate, lauryl methacrylate,
ethylene glycol acrylate, triallyl isocyanurate, maleimide,
phenylmaleimide, p-quinonedioxime, maleic anhydride and itaconic
acid.
[0071] As the compound having silicon hydride, which is used for
crosslinking the ethylenically unsaturated group, a compound having
at least two silicon hydrides can be used. Particularly, a
polysiloxane compound and a polysilane compound are preferable.
[0072] Examples of the polysiloxane compound include a linear
polysiloxane compound represented by the formula (a-1) or (a-2), or
a cyclic polysiloxane compound represented by the formula (a-3).
16
[0073] In the formulas (a-1) to (a-3), R.sup.11, R.sup.12,
R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, R.sup.18and
R.sup.19respectively represent a hydrogen atom or an alkyl or
alkoxy group having 1 to 12 carbon atoms; and n.gtoreq.2,
m.gtoreq.0, 2.ltoreq.m+n.ltoreq.300. As the alkyl group, a lower
alkyl group such as methyl group and ethyl group is preferable. As
the alkoxy group, a lower alkoxy group such as methoxy group and
ethoxy group is preferable.
[0074] As the polysilane compound, a linear silane compound
represented by the formula (b-1) is used. 17
[0075] In the formula (b-1), R.sup.20, R.sup.21, R.sup.22, R.sup.23
and R.sup.24 respectively represent a hydrogen atom or an alkyl or
alkoxy group having 1 to 12 carbon atoms; and
n.ltoreq.2,m.ltoreq.0, 2.ltoreq.m+n.ltoreq.100.
[0076] Examples of the catalyst for the hydrosilylation reaction
include transition metals such as palladium and platinum, or a
compound or complex thereof. Furthermore, a peroxide, an amine and
a phosphine can also be used. The most popular catalyst includes
dichlorobis(acetonitrile- )palladium(II),
chlorotris(triphenylphosphine)rhodium(I) and chloroplatinic
acid.
[0077] In the crosslinking method of the copolymer containing a
halogen atom (e.g. bromine atom or iodine atom), for example, a
crosslinking agent such as polyamines, mercaptoimidazolines,
mercaptopyrimidines, thioureas and polymercaptanes can be used.
Examples of the polyamines include hexamethylenediamine carbamate,
triethylenetetramine, tetraethylene-pentamine, ethylenediamine
carbamate, diethylenetriamine, dipropylene-triamine,
dimethylaminopropylamine, diethylaminopropylamine,
dibutylamino-propylamine, hexamethylenediamine,
trimethylhexamethylenedia- mine, diaminophenyl sulfone,
m-phenylenediamine, 2,4-toluylenediamine, m-toluylenediamine,
o-toluylenediamine and xylylenediamine. Examples of the
mercaptoimidazolines include 2-mercaptoimidazoline,
4-methyl-2-mercaptoimidazoline and
5-ethyl-4-butyl-2-mercaptoimidazoline. Examples of the
mercaptopyrimidines include 2-mercaptopyrimidine,
4,6-dimethyl-2-mercaptopyrimidine and 5-butyl-2-mercaptopyrimidine.
Examples of the thioureas include thiourea, ethylene thiourea,
dibutyl thiourea, trimethyl thiourea, triethyl thiourea and
tributyl thiourea. Examples of the polymercaptanes include
2-dibutylamino-4,6-dimethylcapto-- s-triazine,
2-phenylamino-4,6-dimercaptotriazine, 2,5-dimercapto-1,3,4-thi-
azole, 1,10-decanedithiol, 2,3-dimercaptopyrazine,
2,3-dimercaptoquinoxali- ne and
6-methylquinoxaline-2,3-dithiocarbonate. The amount of the
crosslinking agent varies depending on the type of the crosslinking
agent, but is normally from 0.1 to 30% by weight based on the whole
composition excluding a plasticizer.
[0078] It is effective to add a metal compound as an acid acceptor
to the polymer solid electrolyte in view of the thermal stability
of the halogen-containing polymer. Examples of the metal oxide as
the acid acceptor include oxide, hydroxide, carbonate salt,
carboxylate salt, silicate, borate salt and phosphite salt of Group
II metal of the periodic table; and oxide, basic carbonate salt,
basic carboxylate salt, basic phosphite salt, basic sulfite salt
and tribasic sulfate salt of Group VIa metal of the periodic table.
Specific examples thereof include magnesia, magnesium hydroxide,
barium hydroxide, magnesium carbonate, barium carbonate, quick
lime, slaked lime, calcium carbonate, calcium silicate, calcium
stearate, zinc stearate, calcium phthalate, magnesium phosphite,
calcium phosphite, zinc white, tin oxide, litharge, red lead, white
lead, dibasic lead phthalate, dibasic lead carbonate, tin stearate,
basic lead phosphite, basic tin phosphite, basic lead sulfite and
tribasic lead sulfate. The amount of the metal compound as the acid
acceptor varies depending on the type thereof, but is normally from
0.1 to 30% by weight based on the whole composition excluding a
plasticizer.
[0079] The electrolyte salt compound used in the present invention
is preferably soluble in a mixture comprising a polyether copolymer
or a crosslinked material of the copolymer, and a plasticizer. In
the present invention, the following salt compounds are preferably
used.
[0080] That is, examples thereof include a compound comprising a
cation selected from a metal cation, ammonium ion, amidinium ion
and guanidium ion, and an anion selected from chlorine ion, bromine
ion, iodine ion, perchlorate ion, thiocyanate ion,
tetrafluoroborate ion, nitrate ion, AsF6.sup.-, PF.sub.6.sup.-,
stearylsulfonate ion, octylsulfonate ion, dodecylbenzenesulfonate
ion, naphthalenesufonate ion, dodecyinaphthalenesulfonate ion,
7,7,8,8-tetracyano-p-quinodimethane ion, X.sup.1SO.sub.3.sup.-,
(X.sup.1SO.sub.2) (X.sup.2SO.sub.2)N.sup.-,
(X.sup.1SO.sub.2)(X.sup.2SO.sub.2)(X.sup.2SO.sub.2)
(X.sup.3SO.sub.2)C.sup.- and
(X.sup.1SO.sub.2)(X.sup.2SO.sub.2)YC.sup.-, wherein X.sup.1,
X.sup.2, X.sup.3 and Y respectively represent an electron
attractive group. Preferably, X.sup.1, X.sup.2 and X.sup.3
independently represent a perfluoroaryl group or a perfluoroalkyl
group having 1 to 6 carbon atoms and Y represents a nitro group, a
nitroso group, a carbonyl group, a carboxyl group or a cyano group.
X.sup.1, X.sup.2 and X.sup.3 may be the same or different. As the
metal cation, a cation of a transition metal can be used.
Preferably, a cation of a metal selected from Mn, Fe, Co, Ni, Cu,
Zn and Ag metals is used. When using a cation of a metal selected
from Li, Na, K, Rb, Cs, Mg, Ca and Ba metals, good results are
obtained. Two or more compounds described above may be used as the
electrolyte salt compound.
[0081] The plasticizer is an aprotic organic solvent, or a
derivative or metal salt of a straight-chain or branched
polyalkylene glycol having a number-average molecular weight of 200
to 5,000, or a metal salt of the derivative.
[0082] As the aprotic organic solvent, aprotic ethers and esters
are preferable. Specific examples include propylene carbonate,
.gamma.-butyrolactone, butylene carbonate, ethylene carbonate,
dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate,
1,2-dimethoxyethane, 1,2-dimethoxypropane, 3-methyl-2-oxazolidone,
tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane,
4,4-methyl-1,3-dioxolane, tert-butyl ether, iso-butylether,
1,2-ethoxymethoxyethane, ethylene glycol dimethyl ether, ethylene
glycol diethyl ether, triethylene glycol dimethyl ether,
triethylene glycol diethyl ether, tetraethylene glycol dimethyl
ether, tetraethylene glycol diethyl ether, ethylene glyme, ethylene
diglyme, methyl tetraglyme, methyl triglyme, methyl diglyme, methyl
formate, methyl acetate and methyl propionate. A mixture of two or
more of them may be used. Particularly, propylene carbonate,
y-butyrolactone, butylene carbonate and 3-methyl-2-oxazolidone are
preferable. Triethylene glycol dimethyl ether, triethylene glycol
diethyl ether, tetraethylene glycol dimethyl ether and
tetraethylene glycol diethyl ether are also particularly preferable
organic solvents.
[0083] The derivative or metal salt of the straight-chain or
branched polyalkylene glycol or the metal salt of the derivative
can be obtained from a polyalkylene glycol having a number-average
molecular weight of 200 to 5,000. Examples of the polyalkylene
glycol include polyethylene glycol or polypropylene glycol.
Examples of the derivative thereof include an ester derivative or
ether derivative containing an alkyl group having 1 to 8 carbon
atoms or an alkenyl group having 3 to 8 carbon atoms.
[0084] Among the derivatives, examples of the ether derivative
include diethers such as dimethyl ether, diethyl ether, dipropyl
ether and diallyl ether of polyalkylene glycol, and examples of the
ester derivatives include diesters such as dimethacrylate ester,
diacetate ester and diacrylate ester of polyalkylene glycol.
[0085] Examples of the metal salt of the derivative include sodium,
lithium and dialkylaluminum salts of monoethers of polyalkylene
glycol, such as monomethyl ether, monoethyl ether and monopropyl
ether, monobutyl ether, monohexyl ether, mono-2-ethyl-hexyl ether
and monoallyl ether; and monoesters of polyalkylene glycol such as
monoacetate ester, monoacrylate ester and monomethacrylate
ester.
[0086] Examples of the metal salt include sodium, lithium and
dialkyl aluminum salt of polyalkylene glycol.
[0087] The number-average molecular weight of the polyalkylene
glycol used is more preferably within the range from 200 to
2,000.
[0088] In the present invention, the amount of the electrolyte salt
compound is so that a value of a molar ratio of the number of moles
of the electrolyte salt compound to the total number of moles of
oxyethylene units (the total number of moles of oxyethylene units
including the main chain and side chain of the polyether copolymer)
is preferably within the range from 0.0001 to 5, more preferably
from 0.001 to 0.5. When this value exceeds 5, the processability
and moldability, and the mechanical strength and flexibility of the
resulting solid electrolyte are deteriorated. Furthermore, the
ionic conductivity is also deteriorated.
[0089] The amount of the plasticizer is optionally selected, but is
preferably from 1 to 2,000 parts by weight, e.g. 10 to 1,000 parts
by weight, particularly from 10 to 500 parts by weight, based on
100 parts by weight of the polyether copolymer.
[0090] The flame retardance is required when using the polymer
solid electrolyte, a flame retardant can be used. An effective
amount of those selected from halide (e.g. brominated epoxy
compound, tetrabromobisphenol A and chlorinated paraffin), antimony
trioxide, antimony pentaoxide, aluminum hydroxide, magnesium
hydroxide, phosphate ester, polyphosphate salt and zinc borate are
added.
[0091] The method for production of the polymer solid electrolyte
of the present invention is not specifically limited, and, usually,
the respective components may be mechanically mixed. In case of the
multicomponent-copolymer requiring crosslinking, it is produced by
a method of mechanically mixing the respective components, followed
by crosslinking. Alternatively, after crosslinking, the crosslinked
copolymer may be impregnated by immersing in a plasticizer for a
long time. As means for mechanically mixing, various kneaders, open
roll, extruder and the like can be optionally used.
[0092] In case that the reactive functional group is a reactive
silicon group, the amount of water used in the crosslinking
reaction is not specifically limited because the crosslinking
reaction occurs even in the presence of moisture in the atmosphere.
The crosslinking can also be conducted by passing through a cold
water or hot water bath for a short time, or exposing to a steam
atmosphere.
[0093] In case of the copolymer wherein the reactive functional
group is an epoxy group-containing group, the crosslinking reaction
is completed at the temperature of 10 to 200.degree. C. within 10
minutes to 20 hours when the polyamine or acid anhydride is used.
In case that the reactive functional group is an ethylenically
unsaturated group, the crosslinking reaction is completed at the
temperature of 10 to 200.degree. C. within 1 minute to 20 hours
when radical initiator is used. When using energy ray such as
ultraviolet ray, a sensitizer is normally used. The crosslinking
reaction is normally completed at the temperature of 10 to
150.degree. C. within 0.1 seconds to 1 hour. In case of the
crosslinking agent having silicon hydride, the crosslinking
reaction is completed at the temperature of 10 to 180.degree. C.
within 10 minutes to 10 hours.
[0094] The method of mixing the electrolyte salt compound and
plasticizer with the polyether copolymer is not specifically
limited, but examples thereof include a method of immersing the
polyether copolymer in an organic solvent containing the
electrolyte salt compound and plasticizer for a long time, a method
of mechanically mixing the electrolyte salt compound and
plasticizer with the polyether copolymer, a method of dissolving
and mixing the polyether copolymer and electrolyte salt compound in
the plasticizer, and a method of dissolving the polyether copolymer
once in the other organic solvent and mixing the resulting solution
with the plasticizer. When using the organic solvent, various polar
solvents such as tetrahydrofuran, acetone, acetonitrile,
dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone
and methyl isobutyl ketone may be used alone or in combination
thereof.
[0095] The polymer solid electrolyte according to the present
invention is superior in mechanical strength and flexibility so
that a large area thin-film solid electrolyte can be easily
obtained by utilizing the properties. For example, it is possible
to make a battery using the polymer electrolyte of the present
invention. In this case, examples of the positive electrode
material include lithium-manganese double oxide, lithium cobaltate,
vanadium pentaoxide, polyacene, polypyrene, polyaniline,
polyphenylene, polyphenylene sulfide, polyphenylene oxide,
polypyrrole, polyfuran and polyazulene. Examples of the negative
electrode material include an interlaminar compound prepared by
occlusion of lithium between graphite or carbon layers, a lithium
metal and a lithium-lead alloy. The crosslinked polymer solid
electrolyte can also be used as a diaphragm of an ion electrode of
cation such as alkaline metal ion, Cu ion, Ca ion and Mg ion with
taking advantage of high electrical conductivity. The polymer solid
electrolyte of the present invention is suitable as a material for
electrochemical device (e.g. battery, capacitor and sensor).
PREFERRED EMBODIMENTS OF THE INVENTION
[0096] The present invention will be illustrated by the following
Examples.
[0097] The results of Examples and Comparative Examples are shown
in Table 1 to Table 5. The glass transition temperature and fusion
heat were measured in a nitrogen atmosphere within the temperature
range from -100.degree. C. to 80.degree. C. at a heating rate of
10.degree. C./min., using a differential scanning calorimeter DSC
8230B manufactured by Rigaku Denki Co., Ltd. The measurement of the
conductivity .sigma. was conducted as follows. That is, a gel-like
film at 20.degree. C. was sandwiched between platinum electrodes
and the conductivity was calculated according to the complex
impedance method, using an A.C. method (voltage: 0.5 V, frequency:
5 Hz to 1 MHz).
[0098] The composition (in terms of monomer) of the copolymer was
determined by .sup.1H NMR spectrum. In case of the measurement of
the molecular weight of the copolymer, the gel permeation
chromatography measurement was conducted and the molecular weight
was calculated in terms of standard polystyrene. The gel permeation
chromatography measurement was conducted at 60.degree. C. by a
measuring device RID-6A manufactured by Shimadzu Corp., using a
column (manufactured by Showa Denko Co., Ltd.) such as Showdex
KD-807, KD-806, KD-806M and KD-803, and a solvent DMF.
[0099] Preparation Example (Production of Catalyst)
[0100] Tributyltin chloride (10 g) and tributyl phosphate (35 g)
were charged in a three-necked flask equipped with a stirrer, a
thermometer and a distillation device, and the mixture was heated
at 250.degree. C. for 20 minutes while stirring under a current of
nitrogen and the distillate was distilled off to obtain a solid
condensate. This organotin-phosphate ester condensate was used as a
polymerization catalyst.
EXAMPLE 1
[0101] After the atmosphere in a four-necked glass flask (internal
volume: 3 L) was replaced by nitrogen, an organotin-phosphate ester
condensate (1 g) as the catalyst, diethylene glycol glycidyl methyl
ether (42 g) having water content adjusted to not more than 10 ppm
and n-hexane (1,000 g) as the solvent were charged in the flask,
and ethylene oxide (200 g) was gradually added with monitoring the
polymerization degree of diethylene glycol glycidyl methyl ether by
gas chromatography. The polymerization reaction was terminated by
using methanol. The polymer was isolated by decantation, dried at
40.degree. C. under a normal pressure for 24 hours, and then dried
at 45.degree. C. under reduced pressure for 10 hours to obtain 200
g of a polymer. The glass transition temperature of this copolymer
was -61.degree. C., the number-average molecular weight measured by
the gel permeation chromatography was 1,100,000 and the fusion heat
was 0 J/g. The results of the composition analysis (in terms of
monomer) of this polymer by .sup.1H NMR spectrum are as shown in
Example 1 of Table 1. The resulting polyether copolymer (1 g) was
mixed with a propylene carbonate solution (1.5 ml) of lithium
perchlorate so that a molar ratio of the number of moles of the
soluble electrolyte salt compound to the total number of moles of
ethylene oxide units in the copolymer was 0.05. This mixture liquid
was casted on a mold made of polytetrafluoroethylene, heated and
pressurized at 100.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to
obtain a film.
EXAMPLE 2
[0102] The polyether copolymer (1 g) shown in Table 1 polymerized
by using the organotin-phosphate ester condensate catalyst and
dicumyl peroxide (a crosslinking agent) (0.015 g) were dissolved in
tetrahydrofuran (20 ml), and the resulting solution was mixed with
a tetrahydrofuran solution of lithium perchlorate (5 ml) so that a
molar ratio of the number of moles of the soluble electrolyte salt
compound to the total number of ethylene oxide units was 0.05. This
mixed solution was casted on a mold made of
polytetrafluoroethylene, dried, heated and pressurized at
160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to obtain a film.
This film was immersed in a propylene carbonate liquid for 24 hours
and impregnated with 0.5 ml of the liquid, and then allowed to
stand at 100.degree. C. for 24 hours to obtain a gel-like
electrolyte film.
EXAMPLE 3
[0103] The polyether copolymer (1 g) shown in Table 1 polymerized
by using the organotin-phosphate ester condensate catalyst and
dicumyl peroxide (a crosslinking agent) (0.015 g) were mixed with a
propylene carbonate solution (0.7 ml) of lithium perchlorate so
that a molar ratio of the number of moles of the soluble
electrolyte salt compound to the total number of moles of ethylene
oxide units was 0.05. This mixed solution was casted on a mold made
of polytetarfluoroethylene, heated and pressurized at 160.degree.
C. and 20 KgW/cm.sup.2 for 10 minutes to obtain a gel-like
film.
EXAMPLE 4
[0104] The polyether copolymer (1 g) shown in Table 1 polymerized
by using the organotin-phosphate ester condensate catalyst and
dicumyl peroxide (a crosslinking agent) (0.015 g) were dissolved in
tetrahydrofuran (20 ml), and the resulting solution was casted on a
mold made of polytetarfluoroethylene, heated and pressurized at
160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to remove
tetrahydrofuran and to obtain a film. This film was immersed in a
.gamma.-butyrolactone solution of lithium perchlorate and
impregnated with 2 ml of the electrolyte salt solution so that a
molar ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.05, thereby obtaining a gel-like film.
EXAMPLES 5 and 6
[0105] To each polyether copolymer (1 g) shown in Table 1
polymerized by using the organotin-phosphate ester condensate
catalyst, a propylene carbonate solution (0.6 ml) of lithium
bistrifluoromethane sulfonylimide was added so that a molar ratio
of the number of moles of the soluble electrolyte salt compound to
the total number of moles of ethylene oxide units was 0.05. To the
resulting solution, water was added in an equimolar amount based on
the reactive silicon group-containing component. This mixed gel was
casted on a mold made of polytetarfluoroethylene, heated and
pressurized at 160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to
obtain a gel-like film.
EXAMPLES 7 and 8
[0106] Each polyether copolymer (1 g) shown in Table 1 polymerized
by using the organotin-phosphate ester condensate catalyst and
diethyltriamine (a crosslinking agent) (50 mg) were mixed with a
y-butyrolactone solution (0.5 ml) of lithium perchlorate in Example
7 or a tetraethylene glycol dimethylether solution (0.5 ml) of
lithium perchlorate in Example 8 so that a molar ratio of the
number of moles of the soluble electrolyte salt compound to the
total number of moles of ethylene oxide units was 0.05. This mixed
gel was casted on a mold made of polytetarfluoroethylene, heated
and pressurized at 1600.degree. C. and 20 KgW/cm.sup.2 for 10
minutes to obtain a gel-like film.
Comparative Example 1
[0107] The polyethylene oxide (1 g) shown in Table 2 polymerized by
using the organotin-phosphate ester condensate catalyst was mixed
with a tetrahydrofuran solution of lithium perchlorate so that a
molar ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.005. This solution was casted on a mold made of
polytetrafluoroethylene, dried to sufficiently remove
tetrahydrofuran and pressure-molded to obtain a film.
Comparative Example 2
[0108] The same operation as in Comparative Example 1 was
conducted, except for using the polyether copolymer shown in Table
2 polymerized by using the organotin-phosphate ester condensate
catalyst, but no film was obtained.
Comparative Example 3
[0109] The polyether copolymer (1 g) shown in Table 2 polymerized
by using the organotin-phosphate ester condensate catalyst and
dicumyl peroxide (a crosslinking agent) (0.015 g) were dissolved in
tetrahydrofuran (20 ml), and the resulting solution was mixed with
a tetrahydrofuran solution of lithium perchlorate so that a molar
ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.05. This mixed solution was casted on a mold made of
polytetrafluoroethylene, dried to sufficiently remove
tetrahydrofuran, heated and pressurized at 160.degree. C. and 20
KgW/cm.sup.2 for 10 minutes to obtain a film.
Comparative Example 4
[0110] The polyether copolymer (the same copolymer as that of
Example 3) (1 g) shown in Table 2 polymerized by using the
organotin-phosphate ester condensate catalyst and dicumyl peroxide
(a crosslinking agent) (0.015 g) were mixed with a tetrahydrofuran
solution (5 ml) of lithium perchlorate so that a molar ratio of the
number of moles of the soluble electrolyte salt compound to the
total number of moles of ethylene oxide units was 0.05. This mixed
solution was casted on a mold made of polytetrafluoroethylene and
dried and heated at 160.degree. C. and 20 Kg/cm.sup.2 for 10
minutes to obtain a film.
Comparative Example 5
[0111] In same manner as that described in example 3 except for
using the polyether polymer in Table 2 polymerized by using the
organotin-phosphate ester condensate catalyst, a gel-like film was
obtained.
EXAMPLE9
[0112] Using the gel-like polymer solid electrolyte obtained in
Example 3 as an electrolyte, a lithium metal foil as a negative
electrode and lithium cobaltate (LiCoO.sub.2) as a positive
electrode, a secondary battery was constructed. The size of the
gel-like polymer solid electrolyte was 10 mm.times.10 mm.times.1
mm. The size of the lithium foil was 10 mm.times.10 mm.times.0.1
mm. Lithium cobaltate was prepared by mixing predetermined amount
of lithium carbonate and cobalt carbonate powder and calcining the
mixture at 900.degree. C. for 5 hours. The calcined mixture was
ground, and then 12 parts by weight of acetylene black and 3 parts
by weight of the crosslinked polymer solid electrolyte obtained in
Example 3 were added to 85 parts by weight of the resulting lithium
cobaltate, followed by mixing using a roll and further
press-molding under the pressure of 300 KgW/cm.sup.2 to form the
positive electrode having the size of 10 mm.times.10 mm.times.2
mm.
[0113] The gel-like polymer solid electrolyte obtained in Example 3
was sandwiched between the lithium metal foil and the lithium
cobaltate plate, and the charge/discharge characteristics of the
resulting battery were examined with applying the pressure of 10
KgW/cm.sup.2 so that the interfaces are brought into contact with
each other. The discharge current at the initial terminal voltage
of 3.2 V was 0.5 mA/cm.sup.2 and the charging could be conducted at
0.4 mA/cm.sup.2. It is possible to reduce the thickness of the
battery in this Example and, therefore, a light-weight and
large-capacity battery can be obtained.
1 TABLE 1 Example No. 1 2 3 4 5 6 Composition of formed copolymer
(% by mol) Monomer of the formula (1) 95 10 9 8 9.9 14.7 Ethylene
oxide 5 90 90 87 90 85 Allyl glycidyl ether 1 Glycidyl methacrylate
5 .gamma.-Glycidoxypropylmethyldimethoxysilane 0.3
.gamma.-Glycidoxypropyltrimethoxysilane 0.1 Oxyethylene unit of the
side chain portion of the formula (1) Polymerization degree: n 2 2
2 4 8.5 2 Substituent: R.sup.1 --CH.sub.3
--CH.sub.2--CH.dbd.CH.sub.2 --CH.sub.3 --CH.sub.3 --CH.sub.3 18
Number-average molecular weight of copolymer 1,100,000 300,000
350,000 660,000 170,000 390,000 Glass transition temperature of
copolymer (.degree. C.) -61 -67 -67 -68 -63 -61 Fusion heat of
copolymer (J/g) 0 39 47 38 10 7 Amount (g) of organic solvent per 1
g of polymer 1.5 0.5 0.7 2 0.6 0.6 Conductivity of solid
electrolyte film (S/cm) 1.1 .times. 10.sup.-2 9.8 .times. 10.sup.-3
7.7 .times. 10.sup.-3 1.0 .times. 10.sup.-2 2.1 .times. 10.sup.-3
4.5 .times. 10.sup.-3 20.degree. C. Example No. 7 8 Composition of
formed copolymer (% by mol) Monomer of the formula (1) 45 15
Ethylene oxide 52 78 2,3-Epoxypropyl-2', 3 3'-epoxy-2'-methyl
propyl ether Diethylene glycol 2,3-epoxypropyl-2', 7
3'-epoxy-2'-methyl propyl ether Oxyethylene unit of the side chain
portion of the formula (1) Polymerization degree: n 3 2
Substituent: R.sup.1 --CH.sub.3 --(CH.sub.2).sub.3--CH.sub.3
Number-average molecular weight of copolymer 320,000 280,000 Glass
transition temperature of copolymer (.degree. C.) -70 -68 Fusion
heat of copolymer (J/g) 3 13 Amount (g) of organic solvent per 1 g
of polymer 0.5 0.5 Conductivity of solid electrolyte film (S/cm)
20.degree. C. 3.0 .times. 10.sup.-2 7.6 .times. 10.sup.-3 Note:
Monomer of the formula (1): 19 (1)
[0114]
2 TABLE 2 Comparative Example No. 1 2 3 4 5 Composition of formed
copolymer (% by mol) Monomer of the formula (1) 100 9 Ethylene
oxide 100 98 90 58 Allyl glycidyl ether 2 1 3 Epichlorohydrin 39
Oxyethylene unit of the side chain portion of the formula (1)
Polymerization degree: n 2 2 Substituent: R.sup.1 --CH.sub.3
--CH.sub.3 Number-average molecular weight of copolymer 200,000
100,000 950,000 350,000 220,000 Glass transition temperature of
copolymer (.degree. C.) -59 -74 -62 -67 -49 Fusion heat of
copolymer (J/g) 164 0 153 47 0 Amount (g) of organic solvent per 1
g of polymer 0 0 0 0 0.7 Conductivity of solid electrolyte film
(S/cm) 1.1 .times. 10.sup.-6 impossible to 1.8 .times. 10.sup.-6
1.5 .times. 10.sup.-4 8.5 .times. 10.sup.-5 20.degree. C. form film
Note: Monomer of the formula (1): 20 (1)
Example 10
[0115] After the atmosphere in a four-necked glass flask (internal
volume: 3 L) was replaced by nitrogen, an organotin-phosphate ester
condensate (1 g) as the catalyst, diethylene glycol glycidyl methyl
ether (42 g) whose water content was adjusted to not more than 10
ppm and n-hexane (1000 g) as the solvent were charged in the flask,
and ethylene oxide (200 g) was gradually added with monitoring the
polymerization degree of diethylene glycol glycidyl methyl ether by
gas chromatography. The polymerization reaction was terminated by
using methanol. The polymer was isolated by decantation, dried at
40.degree. C. under a normal pressure for 24 hours, and then dried
at 45.degree. C. under reduced pressure for 10 hours to obtain 200
g of a polymer. The glass transition temperature of this copolymer
was -61.degree. C., the number-average molecular weight obtained by
gel permeation chromatography was 1,100,000 and the fusion heat was
0 J/g. The results of the composition analysis (in terms of
monomer) of this polymer by .sup.1H NMR spectrum are as shown in
Example 10 of Table 3. The resulting polyether copolymer (1 g) and
polyethylene glycol diethyl ether (number-average molecular weight
as polyalkylene glycol (the same in the following Examples and
Comparative Examples) Mn: 500) (0.4 g) were dissolved in a
tetrahydrofuran (20 ml), and the resulting solution was mixed with
a tetrahydrofuran solution of lithium perchlorate so that a molar
ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.05. This mixed liquid was casted on a mold made of
polytetrafluoroethylene, dried (tetrahydrofuran was removed in this
process), heated and pressurized at 100.degree. C. and 20
KgW/cm.sup.2 for 10 minutes to obtain an electrolyte film.
EXAMPLE 11
[0116] The polyether copolymer (1 g) shown in Table 3 polymerized
by using the organotin-phosphate ester condensate catalyst,
polyethylene glycol dimethacrylate ester (Mn:1,000) (0.3 g) and
dicumyl peroxide (a crosslinking agent) (0.015 g) were dissolved in
tetrahydrofuran (20 ml), and the resulting solution was mixed with
a tetrahydrofuran solution (5 ml) of lithium perchlorate so that a
molar ratio of the number of moles of the soluble electrolyte salt
compound to the total number of ethylene oxide units was 0.05. This
mixed solution was casted on a mold made of
polytetrafluoroethylene, dried, heated and pressurized at
160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to give a
film.
EXAMPLE 12
[0117] The polyether copolymer (1 g) shown in Table 3 polymerized
by using the organotin-phosphate ester condensate catalyst,
polyethylene glycol dimethyl ether (Mn:1,000)(0.3 g) and dicumyl
peroxide (a crosslinking agent) (0.015 g) were dissolved with a
tetrahydrofuran (20 ml), and the resulting solution was mixed with
a tetrahydrofuran solution (5 ml) of lithium perchlorate so that a
molar ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.05. This mixed solution was casted on a mold made of
polytetrafluoroethylene, dried, heated and pressurized at
160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to give a
film.
EXAMPLE 13
[0118] The polyether copolymer (1 g) shown in Table 3 polymerized
by using the organotin-phosphate ester condensate catalyst, a
lithium salt of polyethylene glycol (prepared by adding a 2-fold
molar amount of metal lithium to polyethylene glycol having a
number-average molecular weight of 400, followed by standing at
room temperature for 3 days) (0.2 g) and dicumyl peroxide (a
crosslinking agent) (0.015 g) were dissolved in tetrahydrofuran (20
ml), and the resulting solution was mixed with a tetrahydrofuran
solution (5 ml) of lithium perchlorate so that a molar ratio of the
number of moles of the soluble electrolyte salt compound to the
total number of ethylene oxide units was 0.05. This mixed solution
was casted on a mold made of polytetrafluoroethylene, heated and
pressurized at 160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to
give a film.
EXAMPLES 14 and 15
[0119] Each polyether copolymer (1 g) shown in Table 3 polymerized
by using the organotin-phosphate ester condensate catalyst and a
sodium salt of polyethylene glycol monomethyl ether (prepared by
adding an equimolar amount of metal sodium to polyethylene glycol
monomethyl ether having a number-average molecular weight of 500,
followed by standing at room temperature for 3 days) (0.2 g) were
added to a tetrahydrofuran solution (20 ml) of lithium
bistrifluoromethanesulfonylimide so that a molar ratio of the
number of moles of the soluble electrolyte salt compound to the
total number of ethylene oxide units was 0.05. To the resulting
solution, water was added in an equimolar amount based on the
reactive silicon group-containing component, followed by mixing.
This mixed solution was casted on a mold made of
polytetrafluoroethylene, heated and pressurized at 160.degree. C.
and 20 KgW/cm.sup.2 for 10 minutes to obtain a film.
EXAMPLES 16 and 17
[0120] Each polyether copolymer (1 g) shown in Table 3 polymerized
by using the organotin-phosphate ester condensate catalyst,
diethylenetriamine (50 mg) (a crosslinking agent) and a
tetarhydrofuran solution (10 ml) of lithium perchlorate were mixed
so that a molar ratio of the number of moles of the soluble
electrolyte salt compound to the total number of moles of ethylene
oxide units was 0.05. In Example 16, the resulting solution was
mixed with polyethylene glycol dimethyl ether (Mn:600) (0.2 g). In
Example 17, the resulting solution was mixed with a dioctyl
aluminum salt of polyethylene glycol (prepared by adding a two-fold
molar amount of trioctyl aluminum to polyethylene glycol having a
number-average molecular weight of 400, followed by drying under
reduced pressure) (0.2 g). These mixed solutions were casted on a
mold made of polytetrafluoroethylene, heated and pressurized at
160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes to obtain a film,
respectively.
Comparative Example 6
[0121] The polyethylene oxide (1 g) shown in Table 4 polymerized by
using the organotin-phosphate ester condensate catalyst was mixed
with a tetrahydrofuran solution of lithium perchlorate so that a
molar ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.005. Furthermore, polyethylene glycol dimethyl ether
(Mn:1,000)(0.2 g) was dissolved in tetrahydrofuran (20 ml) and this
solution was added. This mixed solution was casted on a mold made
of polytetrafluoroethylene and then pressure-molded to obtain a
film.
Comparative Example 7
[0122] The same operation as that described in Comparative Example
6 was conducted, except for using the polyether polymer shown in
Table 4 polymerized by using the organotin-phosphate ester
condensate catalyst, but a film was not obtained.
Comparative Example 8
[0123] The polyether copolymer (1 g) shown in Table 4 polymerized
by using the organotin-phosphate ester condensate catalyst and
dicumyl peroxide (a crosslinking agent) (0.015 g) were dissolved in
tetrahydrofuran (20 ml), and the resulting solution was mixed with
a tetrahydrofuran solution of lithium perchlorate so that a molar
ratio of the number of moles of the soluble electrolyte salt
compound to the total number of moles of ethylene oxide units was
0.05. Furthermore, polyethylene glycol dimethyl ether
(Mn:1,000)(0.2 g) was dissolved in tetrahydrofuran (20 ml) and this
solution was added. This mixed solution was casted on a mold made
of polytetrafluoroethylene, dried to sufficiently remove
tetrahydrofuran, heated and pressurized at 160.degree. C. and 20
KgW/cm.sup.2 for 10 minutes to give a film.
Comparative Example 9
[0124] The polyether copolymer (1 g) shown in Table 4 polymerized
by using the organotin-phosphate ester condensate catalyst (the
same copolymer as in Example 12) and dicumyl peroxide (a
crosslinking agent) (0.015 g) were mixed with a tetrahydrofuran
solution (5 ml) of lithium perchlorate so that a molar ratio of the
number of moles of the soluble electrolyte salt compound to the
total number of moles of ethylene oxide units was 0.05. This mixed
solution was casted on a mold made of polytetrafluoroethylene,
dried, heated at 160.degree. C. and 20 KgW/cm.sup.2 for 10 minutes
to obtain a film.
Comparative Example 10
[0125] In the same manner as that described in Example 12 except
for using the polyether copolymer shown in Table 4 polymerized by
using the organotin-phosphate ester condensate catalyst, a film was
obtained.
EXAMPLES 18 to 20
[0126] Each polyether copolymer (1 g) shown in Table 5 polymerized
by using the organotin-phosphate ester condensate catalyst and an
acetonitrile solution (15 mL) of lithium perchlorate were mixed so
that a molar ratio of the number of moles of the soluble
electrolyte salt compound to the total number of moles of ethylene
oxide units was 0.1. In Example 18, the resulting solution was
mixed with a branched ethylene glycol derivative represented by the
formula (10) (0.3 g) to prepare a mixed solution. In Example 19,
the resulting solution was mixed with a branched ethylene glycol
derivative represented by the formula (11) (0.3 g) to prepare a
mixed solution. In Example 20, the resulting solution was mixed
with a branched ethylene glycol derivative represented by the
formula (12) (0.3 g) to prepare a mixed solution. These mixed
solutions were casted on a mold made of polytetrafluoroethylene and
heated and pressurized at 160.degree. C. and 20 Kg/cm.sup.2 for 10
minutes to obtain a film, respectively. Characteristics of the
films are shown in Table 5. 21
EXAMPLE 21
[0127] Using the polymer solid electrolyte obtained in Example 12
as an electrolyte, a lithium metal foil as a negative electrode and
lithium cobaltate (LiCoO.sub.2) as a positive electrode, a
secondary battery was constructed. The size of the polymer solid
electrolyte was 10 mm.times.10 mm.times.1 mm. The size of the
lithium foil was 10 mm.times.10 mm.times.0.1 mm. Lithium cobaltate
was prepared by mixing predetermined amount of lithium carbonate
and cobalt carbonate powder and calcining the mixture at
900.degree. C. for 5 hours. The calcined mixture was ground, and
then 12 parts by weight of acetylene black and 3 parts by weight of
the crosslinked polymer solid electrolyte obtained in Example 12
were added to 85 parts by weight of the resulting lithium
cobaltate, followed by mixing by a roll and further press-molding
under the pressure of 300 KgW/cm.sup.2 to form the positive
electrode having the size of 10 mm.times.10 mm.times.2 mm.
[0128] The polymer solid electrolyte obtained in Example 12 was
sandwiched between the lithium metal foil and the lithium cobaltate
plate, and the charge/discharge characteristics of the resulting
battery were examined with applying the pressure of 10 KgW/cm.sup.2
so that the interfaces are brought into contact with each other.
The discharge current at the initial terminal voltage of 3.2 V was
0.5 mA/cm.sup.2 and charging could be conducted at 0.4 mA/cm.sup.2.
It is possible to reduce the thickness of the battery in this
Example and, therefore, a light-weight and large-capacity battery
can be obtained.
3 TABLE 3 Example No. 10 11 12 13 14 15 Composition of formed
copolymer (% by mol) Monomer of the formula (1) 95 10 9 8 9.9 14.7
Ethylene oxide 5 90 90 87 90 85 Allyl glycidyl ether 1 Glycidyl
methacrylate 5 .gamma.-Glycidoxypropylmethyldimethoxysilane 0.3
.gamma.-Glycidoxypropyltrimethoxysilane 0.1 Oxyethylene unit of the
side chain portion of the formula (1) Polymerization degree: n 2 2
2 4 8.5 2 Substituent: R.sup.1 --CH.sub.3
--CH.sub.2--CH.dbd.CH.sub.2 --CH.sub.3 --CH.sub.3 --CH.sub.3 22
Number-average molecular weight of copolymer 1,100,000 300,000
350,000 660,000 170,000 390,000 Glass transition temperature of
copolymer -61 -67 -67 -68 -63 -61 (.degree. C.) Fusion heat of
copolymer (J/g) 0 39 47 38 10 7 Amount (g) of polyalkylene glycol
compound per 0.4 0.3 0.3 0.2 0.2 0.2 1 g of copolymer Conductivity
of solid electrolyte film (S/cm) 6.5 .times. 10.sup.-3 4.2 .times.
10.sup.-3 4.7 .times. 10.sup.-3 1.3 .times. 10.sup.-3 1.1 .times.
10.sup.-3 1.4 .times. 10.sup.-3 20.degree. C. Example No. 16 17
Composition of formed copolymer (% by mol) Monomer of the formula
(1) 45 15 Ethylene oxide 52 78 2,3-Epoxypropyl-2',3'-epoxy-2'- 3
methyl propyl ether Diethylene glycol 2,3-epoxypropyl-2', 7
3'-epoxy-2'-methyl propyl ether Oxyethylene unit of the side chain
portion of the formula (1) Polymerization degree: n 3 2
Substituent: R.sup.1 --CH.sub.3 --(CH.sub.2).sub.3--CH.sub.3
Number-average molecular weight of copolymer 320,000 280,000 Glass
transition temperature of copolymer (.degree. C.) -70 -68 Fusion
heat of copolymer (J/g) 3 13 Amount (g) of polyalkylene glycol
compound 0.2 0.2 per 1 g of copolymer Conductivity of solid
electrolyte film (S/cm) 4.7 .times. 10.sup.-3 1.0 .times. 10.sup.-3
20.degree. C. Note: Monomer of the formula (1): 23 (1)
[0129]
4 TABLE 4 Comparative Example No. 6 7 8 9 10 Composition of formed
copolymer (% by mol) Monomer of the formula (1) 100 9 Ethylene
oxide 100 98 90 58 Allyl glycidyl ether 2 1 3 Epichlorohydrin 39
Oxyethylene unit of the side chain portion of the formula (1)
Polymerization degree: n 2 2 Substituent: R.sup.1 --CH.sub.3
--CH.sub.3 Number-average molecular weight of copolymer 200,000
100,000 950,000 350,000 220,000 Glass transition temperature of
copolymer (.degree. C.) -59 -74 -62 -67 -49 Fusion heat of
copolymer (J/g) 164 0 153 47 0 Amount (g) of polyalkylene glycol
compound per 0.2 0.2 0.2 0 0.7 1 g of copolymer Conductivity of
solid electrolyte film (S/cm) 9.5 .times. 10.sup.-5 impossible to
1.0 .times. 10.sup.-4 1.5 .times. 10.sup.-4 1.2 .times. 10.sup.-6
20.degree. C. form film Note: Monomer of the formula (1): 24
(1)
[0130]
5 TABLE 5 Example No. 18 19 20 Composition of formed copolymer (%
by mol) Monomer of the formula (1) 11 20 24 Ethylene oxide 89 80 76
Oxyethylene unit of the side chain portion of the formula (1)
Polymerization degree: n 3 2 2 Substituent: R.sup.1 --CH.sub.3
--CH.sub.3 --CH.sub.3 Number-average molecular weight of copolymer
1,300,000 1,200,000 880,000 Glass transition temperature of
copolymer (.degree. C.) -68 -69 -73 Fusion heat of copolymer (J/g)
40 17 9 Amount (g) of polyalkylene glycol compound per 1 g of 0.3
0.3 0.3 copolymer Conductivity of solid electrolyte film (S/cm) 7.6
.times. 10.sup.-3 6.1 .times. 10.sup.-3 5.2 .times. 10.sup.-3
20.degree. C. Note: Monomer of the formula (1): 25 (1)
EFFECT OF THE INVENTION
[0131] The polymer solid electrolyte of the present invention is
superior in processability, moldability, mechanical strength,
flexibility, heat resistance, etc., and the ionic conductivity is
remarkably improved. Accordingly, it can be applied to electronic
apparatuses such as large-capacity condenser and display device
(e.g. electrochromic display), including solid batteries
(particularly, secondary battery).
* * * * *