JPH02215836A - Polyelectrolyte - Google Patents

Abstract

PURPOSE:To attempt to form a polyelectrolyte with high ionic conductivity even at a low-temp. region which is at room temp. or lower by compounding a polymeric compd. constituted of a specified repeating unit wherein the main chain is a polysiloxane and ethylene oxide chains exist on the side chain and a specified salt of a metal ion. CONSTITUTION:A polyelectrolyte contg. a polymeric compd. having a repeating unit wherein at least the main chain is a polysiloxane and ethylene oxide chains exist at least on one side chain and a salt of an ion of a group 1a or IIa metal of the periodic table and at least one side chain of this polymeric compd. is connected to the main chain through a silicon-carbon covalent bonding and two or more ethylene oxide groups are incorporated in one side chain. It is pref. that said polymeric compd. has at least a repeating unit of formula I, wherein L1 and L2 are each a divalent bonding group; L3 and L4 are each a trivalent bonding group; R1 and R2 are each hydrogen, an alkyl group, etc.; m is 1-16; m' is 0-16; X1, X2, X3 and X4 are each -O-, -S-, etc.; a, b, c, a', b', n, l and l' are each 0 or 1; d is 1 when l' is 0 and 2 when l' is 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to polymer electrolytes, and particularly to polymer electrolytes that can withstand use in a wide temperature range and are chemically stable.

[Conventional technology]

In order to apply polymer electrolytes to static electricity prevention in plastics, batteries, and electrochemical devices, they must exhibit good ionic conductivity over a wide temperature range from low to high temperatures, and have good storage stability. It is necessary that the material be easy to manufacture. However, no polymer electrolyte that comprehensively satisfies these required performances has been developed to date.

For example, conventionally, organic solvents such as 1,2-dimethoxyethane and propylene carbonate have been widely used;
Recently, there has been active research into polymer electrolytes, mainly polyethylene oxide (hereinafter abbreviated as PEO), as a way to improve the shortcomings of these organic solvents. It is.

PEO is a salt of various metals belonging to group Ia or group Ira of the periodic table, such as L i CF3 SO3, L i L
L iCj! 04, N a I, NaCFzSOs
, KCFff So, etc., and exhibits relatively good ion conductivity in a certain temperature range.For example, P. Vashista et al. Transport i
n 5olid), 1 3 1 true (197
(Reported in 1999), and also has good storage stability. However, the ionic conductivity of PEO is highly temperature dependent, and although it shows good ionic conductivity above 60°C, the ionic conductivity deteriorates significantly below 20°C, making it difficult to use it in a wide temperature range. It was difficult to incorporate it into versatile products. Low molecular weight PE
As a method of improving ionic conductivity using ○, a method of introducing low molecular weight PEO into the side chain of a vinyl polymer was proposed by D.G. Bannister (D, J.
Polymer (Polymer)
mer) + vol. 25, p. 1600 (1984),
In addition, a method of introducing low molecular weight PEO into the side chain of polyphosphazene was proposed by D.F. Schreiber (D, F.
Journal of
American Chemical Society (JournalO
f ^merican Chemical 5o
Society), Volume 106, Page 6852 (1984). However, although this polymeric material forms a complex with Li salt,
Ion conductivity was insufficient at: Furthermore, a material in which low-molecular lPE0 is introduced into a part of polysiloxane was published in the Journal of Power Source by Watanabe et al.
rnal ofPower 5ourse) 20jJ
K, p. 327 (1987), but the introduction rate of low molecular weight PEO was low in this material, and therefore it could not be applied unless a large amount of polymeric material was used.

Furthermore, a polymer material that alternately combines low molecular weight PEO and silicon compounds was reported by Nagaoka et al. in the Journal of
Polymer Science; Polymer Letter Edition (Journal or Poly+werSci)
ence,, PoIyv+er Letter
Edition), vol. 22, p. 752 (1982)
was reported in Japanese Patent Application Laid-Open No. 60-216462, and P-G-Hole (P
, G. Hall) et al.
It is reported in Vol. 27, p. 98 (1986). These polymer materials provide high ionic conductivity over a wide temperature range from low temperatures below 20°C to high temperatures above 60°C. This is believed to be due to the fact that silicone-based polymers have lower glass transition temperatures (Tg) than other polymers that have been developed. However, these polymer materials cannot avoid deterioration due to decomposition when they are stored or used for long periods in electronic equipment, which is a significant disadvantage for practical use. It was a great material.

[Problems to be Solved by the Invention] A first object of the present invention is to provide a novel polymer electrolyte that has high ionic conductivity even at low temperatures below room temperature.

A second object of the present invention is to provide a novel chemically stable polymer electrolyte that does not deteriorate during storage or long-term use.

[Means to solve the problem]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that at least the main chain is polysiloxane, and at least one side chain is attached to the main chain by a silicon-carbon covalent bond. Achieved by a polymer electrolyte containing a salt of a metal ion belonging to Group Ia or Group Ila of the Periodic Table, which is a polymer compound having repeating units linked together and having two or more ethylene oxide groups per side chain. It was done.

Since the polymer material of the present invention has an ethylene oxide group in its side chain, it has a high dielectric constant and has an excellent ability to dissolve and dissociate a supporting electrolyte. Furthermore, since the main chain is made of polysiloxane, the glass transition point (Fg) is low (which is thought to facilitate the movement of ions).

Furthermore, the main chain of the polymer material of the present invention is made of polysiloxane, and the side chains are linked by silicon-carbon covalent bonds. Surprisingly, the stability over time has been significantly improved compared to the compound introduced in the present invention.The present invention prevents deterioration at high temperatures, which could not be achieved with conventional polymer electrolytes, and has high ionic conductivity at low temperatures. We were able to fundamentally solve the problems of ensuring stability and chemical stability.

The polymer compound of the present invention preferably has a small number of repeating units (both represented by the following general formula [I]).

General Formula (1) %Formula%] (In the formula, L+ and R2 are divalent linking groups, L, and are trivalent linking groups. R1 and R2 are hydrogen, an alkyl group, or an aryl group. , 0m is an integer from 1 to 16, m' is an integer from 0 to 16, and X+
, Xi, Xi and X4 are R1 and the linking group is represented by the general formula (n).

It is an alkyl group or an aryl group. a, b, c.

a', b', nSl and 2' are O or 1, and d is l
Or 2. ) In formula (1), L+ and Lx are divalent linking groups, which may be the same or different, and are preferably an alkylene group, an aralkylene group, or an oxaalkylene group having 1 to 10 carbon atoms. These groups may be substituted. Examples of substituents include a hydroxyl group, an alkoxy group, an alkyl group, a fluorine atom, a chlorine atom, a bromine atom, and the like. Representative preferred divalent linking groups represented by L+ and Lx include methylene, ethylene, propylene, and phenetidine.

L and R4 are trivalent linking groups and may be the same or different. L and R4 are preferably the same or different and represent a divalent linking group, preferably an alkylene group or an aralkylene group, more preferably an alkylene group having 1 to 6 carbon atoms. ,q−”
” and U are each independently 0 or 1.) As a specific example of L and L4,

R,,R,,R,represent a hydrogen atom, an alkyl group, or an aryl group, preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably these groups having 1 to 3 carbon atoms. 1
-12 are preferable, and these groups may be substituted). Examples of the substituent include the substituents listed above.

X1%X□, X, and x4 -Q--3- are each independently O or l. Preferably aSb, a', b
0m where ' is O is 1. ~16 integer, 2 to 10
is particularly preferable, 0m' is an integer from O to 16,
Preferably it is 2-10. d is 1 or 2.

The polymer compound of the present invention may have a plurality of repeating units of the -8 formula (1).

Examples of the remaining repeating units in the polymer compound of the present invention include dialkylpolysiloxane (for example, dimethylpolysiloxane) and polyalkylene oxide, which can improve film-forming properties.

The repeating unit represented by general formula [I] is 50 in the polymer.
It is preferable that the content is mol% or more, more preferably,
It is 80 mol% or more, particularly preferably 100 mol%.

Representative examples of the repeating unit represented by the general formula [I] are shown below, but the repeating unit is not limited to these.

Compound Example I P-1 Compound Example 3 P-3 I5i-0)-CH,-0-CIyoGHz (OCII*CHzhOC
H3Hs Compound Example 4 P-4 CIyo-OCToCHgOCHzCHg OCH! +
sto)-CI+! -0-CH CHiCHxOCHxCHiOCHzC
11゜Compound Example 2 P-2 CHI-0-CH proverb CHt(OCHiCIb)r OC
H! CIlyo CH3CH2OCR CH□-OCHiCHzOCII□Cl1x 0CH
s Compound Example 5 P-5 CI+3 Compound Example 6 P-6 Compound Example 9 CIll OCIhCHx OCHtCHt O
CH3 Book CIItCH*CHt OCI l CHz OCHtClh OCHzCHt 0C
1h Compound Example 10 OCHtCHt”(OCIlxCHt)-rS C
1b Compound Example 7 +Si 0)- CHt 0CHtCHt云0C11□C1l Tsuji T-3
-CI+3C! HS Compound Example 11 Compound Example 14Si -0)- CHt 45 i -0)= Compound Example 12 i2 Compound Example 15 C1b C00CHtCHz40CllzCHa]-
5CH3CIl, CIl□CIl□-CONHCHC0
0CHtCHx40CHzCH yo F"S CHsCH
JHCllzCHtOCHzCHzOCHs-fsi-
0+ Compound Example 13 Compound Example 16 CHxSCHzChOCIItCHiOC11C11
゜Compound Example 14 CHt OC1hCHzOCHOC1I□O-C1l
s The weight average molecular weight Mw (in terms of polystyrene) of the polymer compound of the present invention is preferably 2,000 to 80,000.

The metal ions belonging to Group Ia or Group Ila of the periodic table used in the present invention are preferably lithium, sodium, and potassium ions, and representative metal ion salts include LiCFsSOs, LiPF*, and LiCj! Oa,
Lit, LiBFa, LiCFz COz, Li5CN
,,Nal,NaCF3 SO3,Na C1,Oa
, Na BF4, NaAsF, , KCFs SOx
, K.S.C.N.

KPF, ,KCj! O, KASF6, etc. More preferred is the above Li salt. These are 1
species or a mixture of two or more species, and N Bu
It may be used in combination with other electrolytes such as aBFa, etc.

The ratio of the polymer compound of the present invention to the metal ion salt is preferably such that polyethylene oxide units are contained in a ratio of 2 to 30 times that of the metal ion salt.

More preferably, it is 6 to 20 times. If the ratio is too high, the Tg will increase and the ionic conductivity will decrease, and if the ratio is too low, the effective ion concentration will decrease and the ionic conductivity will also decrease.

The polymer electrolyte of the present invention may be crosslinked by adding a crosslinking agent, or may further include a polymer compound, other amphipathic compound, etc.

As the crosslinking agent that may be added, those having a crosslinking group such as an epoxy group, an isocyanate group, an acid chloride group, an acid anhydride group, or an active ester group can be used. Examples of crosslinking agent compounds are shown below, but the invention is not limited thereto.

(1) Crosslinking agent compound example Compound example (C-1) CHz CON H (CHz ) h N C○CHs
CHt CC0NH (CHt ) & NC0CH,
C0NH (CH,), NCO Compound example (C-3) NGO OCN (CHz)4 CH Co (CHt), NGO The following representative examples are used as the polymer compounds that may be added. The polymer compound is not limited to the above, and those which are compatible with the polymer compound of the present invention can be preferably used.

Compound example (C-4) (CH, -CH).

0COCH.

Compound example (C-5) (CH, -CH).

ffi Compound example (C-6) Compound example (C-7) (CH-CHffi-0).

CH.

Compound example (C-8) CH.

(CHZ-C).

0OCH3 Further, as the amphipathic compound that can be added, any known amphipathic compound can be added.

Typical examples include those shown below, but of course they are not limited to these.

Compound example (C-9) C+hH3sO(CHt CHtO) 1sCHZ Compound example (C-10) CtxHzsO(CHt CHz 0)sec+xH*
Example of s compound (C-11) (CHz CH1 10).

Typical examples of solvents for dissolving the polymer compound and metal ion salt of the present invention include nitriles such as acetonitrile and benzonitrile; carbonates such as propylene carbonate and ethylene carbonate; R: tetrahydrofuran, 3-
Ethers such as methyl-tetrahydrofuran, 2-methyl-tetrahydrofuran, tetrahydropyran, 1,3-dioxane, 1゜4-dioxolane, 1,2-dimethoxyethane W4: Lactones such as r-butyrolactone and δ-butyrolactone, dimethyl These solvents include, but are not limited to, sulfoxide, tetramethylene sulfone, dimethylformamide, etc. These solvents may be used alone or in combination of two or more.

The polymer electrolyte of the present invention can also be used as an antistatic material for plastic materials, batteries, and materials for various electrochemical devices such as electrochromic displays and capacitors.

A typical synthesis example of a polymer compound containing a repeating unit represented by the general formula ([) of the present invention is shown below.

Synthesis Example I 100% of the repeating unit represented by P-1
Synthesis of containing compound (P-1 polymer) Ctlg OCHzCIIiOCHzCHyo0CH3
CIlOCIhCHxOC1hCH*0CHiEpichlorohydrin23. 0 g (0,2'47sol
) to diethylene glycol methyl ether 300
g (2,5 sol) and 12 g (0,3 sol) of 60% oily sodium hydride at 60°
After a dropwise reaction at C for 15 minutes, the mixture was neutralized with dilute hydrochloric acid and extracted with ether. The ether layer was washed with water, dried over magnesium sulfate, and the ether was distilled off to obtain a brown solution. The target product was obtained by vacuum distillation (171-182°C/2 Hg).

Yield: 44.5 g (yield: 60%) The chemical structure was confirmed by NMR, IR, elemental analysis, and GC.

CI-0-CHzCHgOCIhCHzOljlsC
H-CI-CH*-0-Cll
Synthesis of (D-2) Cut-0-CHgC11tOCHt
CHiOCHi compound D l log (0,03
4sol), potassium-t-butoxide 5.4g (
0,048*ol) was dissolved in t-amyl alcohol 50-, and 5.8g of allyl bromide (0,048*ol
) was added dropwise over 10 minutes at room temperature. After that, the reaction was carried out at room temperature for 2 hours and at 90°C for 2 hours, and then the inorganic salt was filtered off, and the residue was purified using a silica gel column (solvent: hexane, ethyl acetate mixed solvent).

(Yield: 98.4gC, Yield: 74%) The chemical structure was confirmed by NMR, IR1 elemental analysis, and GC.

(3) Synthesis of P-1 polymer Polymethylhydrosiloxane 1.2g (0.8gmo
l), Compound D-27,6g (0,027aol)
mixed with chloroplatinic acid 1 osg (0,01m
(2) was dissolved in 54 G of tetrahydrofuran and added to the solution. Thereafter, the reaction mixture was reacted at room temperature for 2 hours and at 60°C for 2 hours, and then purified using a Sephadex column (solvent: methanol, ethanol mixed solvent).

Yield 2.7g (yield 49%) Mw+19,000 Is the chemical structure NML? , confirmed by IR1 elemental analysis.

Synthesis Example 2 100% repeating unit represented by P-4
Synthesis of Compounds Containing (P-4 Polymer) Compound D-210g (0,034aol), dichlorodihydrosilane 1. 7g (0,017sol)
, 5 m of a tetrahydrofuran solution of 51 g (0,005 gmol) of chloroplatinic acid was placed in a sealed tube, and the mixture was heated at room temperature for 2 hours.
After 2 hours of reaction at 60°C, the contents were taken out, 10 ml of water was added, and the mixture was vigorously stirred at 40°C for 2 hours. After that, the solvent was distilled off under reduced pressure, and the Sephadex column (
Solvent: methanol, ethanol mixed solvent).

Yield 5.2g (44%) I got the liquid. (Φ0θ) 24,000 in Mw The chemical structure was confirmed by NMR1IR1 elemental analysis.

〔Example〕

Hereinafter, it will be explained in detail using examples.

Example I P-1 polymer and LiChSOs were dissolved in acetone at room temperature so as to have the composition ratio shown in Table 1. At this time, p
The concentration of -t polymer was 10%.

The solvent was then treated under vacuum (10-'' to 10-3 torr) at room temperature for 24 hours and at 60°C for 24 hours to completely remove the solvent and obtain a clear homogeneous viscous solution. −
1 polymer instead of P-4 polymer, LiCFiS
LiCl instead of Os! An identical solution was obtained except that 04 was substituted. (0θ0) For comparison, P-1 of ■
Molten CH, which is the same as ①, except that the following compound (E-1) described in JP-A No. 61-216462 was used instead of the polymer.

C1+3 Mw ÷ 10,000 Furthermore, instead of the P-1 polymer in ■, Journal of Power, Source
A solution was obtained which was the same as ① except that the following compound (E-2) reported in Vol. 29, p. 327 (1987) was substituted. (@Φθ) (E-2) The viscous liquid thus obtained was put into a 1 cm glass cell and a pt electrode was connected to the 0. The impedance was measured at 0.1 Hz to 100,000 H2 (measurement temperature 20''C), and the ionic conductivity was determined from a Co1eCole plot.

In addition, the stability of the polymer was evaluated by the following method.

Each compound was dissolved in an acetonitrile-water buffer solution with a pH of 4.2 at 25°C (concentration: 5 wt%), and decomposition into monomers was monitored by gel permeation chromatography (GPC).

The results of these measurements are shown in Table 1 and FIG.

As can be seen from Table 1, Examples 1 to 0 of the present invention and Comparative Example ΦOO have good ionic conductivity near room temperature, but from FIG. It can be seen that the decomposition into is significantly worse.

E-2 has good decomposition into seven molecules, but has poor ionic conductivity. It will be clear that these are simultaneously improved in the present invention.

〔Effect of the invention〕

According to the present invention, a polymer electrolyte with excellent ionic conductivity at room temperature or lower and good stability can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows the decomposition of the compounds P-1 polymer, P-4 polymer, E-1 and E-2 in Example 1 to seven polymers. Figure Time (hr) Patent Applicant Fuji Photo Film Co., Ltd. Procedural Amendment Case Relationship with the Person Amending the Name of the Described Invention Case 1995 Application No. 37707 Polymer Electrolyte

Claims (2)

[Claims] (1) At least a polymer compound whose main chain is polysiloxane and has a repeating unit having an ethylene oxide group in at least one side chain, and a polymer compound whose main chain is polysiloxane and which has a repeating unit having an ethylene oxide group in at least one side chain;
In a polymer electrolyte containing a salt of a metal ion belonging to the above group, at least one side chain of the polymer compound is connected to the main chain by a silicon-carbon covalent bond, and each side chain has two ethylene oxide groups. A polymer electrolyte characterized by having more than 100% of the electrolyte. (2) The polymer compound has at least the following general formula [I]
Claim 1 having a repeating unit represented by
Polyelectrolyte as described in section. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, L_1 and L_2 are divalent linking groups, and L_
3 and L_4 are trivalent linking groups, R_1 and R_2
is hydrogen, an alkyl group, or an aryl group, m is an integer from 1 to 16, m' is an integer from 0 to 16, and X_1, X_2, X_3 and X_4 are -O-,
-S- or ▲There are mathematical formulas, chemical formulas, tables, etc.▼. R_3 is hydrogen, an alkyl group, or an aryl group. a, b, c, a', b', n, l and l' are each independently 0 or 1, and d is 1 or 2. )