JPH0335060A - Polymer solid electrolyte - Google Patents

Abstract

PURPOSE:To obtain a polymer solid electrolyte which is suitable for electrochemical devices such as a primary cell or an electrochemical sensor by using a comb-shaped polymer of a specific polyether, an alkali or alkaline earth metal salt and a solvent dissolving the salt. CONSTITUTION:(A) A comb-shaped polymer obtained by reaction of a polyether which has a structure in which the H on the one terminal OH group of the polyether is substituted with methyl or ethyl group and the H on the other terminal OH group is substituted with a group of formula I (R1 is H, methyl, phenyl) or formula II (R2 is methyl or phenyl), and bears reactive double bonds with a low-molecular monomer bearing a reactive double bond, is admixed to (B) an alkali metal or alkaline earth metal and/or an organic ammonium salt and (C) a solvent which can dissolve component B to give the subject composition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to solid polymers used in secondary batteries, secondary batteries, electrochromic displays, electrochemical sensors, iontophores, capacitors, and other electrochemical devices. It concerns electrolytes.

Conventional technology and its problems Gelled polyester ρ in which alkali metal salts, alkaline earth metal salts, etc. are dissolved exhibits relatively high ionic conductivity, so it is difficult to apply as a solid electrolyte. is attracting wide interest.

As polyether μ, polyethylene oxide or
Copolymers of ethylene oxide and propylene oxide are the most widely used.

As a method of using polyether μ as a solid electrolyte,
Broadly speaking, three methods are widely used. Part-1
This is a method in which 3JIllFl is dissolved in high molecular weight polyethylene oxide that is solid at room temperature and used as is. This method does not involve any synthesis reaction or crosslinking reaction, so the l11jIl! It is also easy to form a film, and the film-forming property is also relatively good. However, when used at low temperatures, the conductivity is low due to crystallization of the polyether μ chains. The second method is to form a solid by crosslinking relatively low molecular weight polyether μ. In this method, crosslinking is performed for the purpose of preventing crystallization of polyether and increasing the mobility of molecular chains. This method is highly effective in improving the low-temperature conductivity of polyethylene oxide, which tends to crystallize at low temperatures. However, the mobility of the polymer chains is low because it is suppressed by the bridge Li.

The third method is to graft relatively low molecular weight polyether μ onto the molecular chain that is to become the main chain to form a comb-shaped polymer. Although comb-shaped polymers have the disadvantage of low mechanical strength at low temperatures, they have the highest ionic conductivity among them.

Recent research has increasingly proposed using comb-shaped polymers, which have the highest conductivity. Typical examples include those using main chain polyphosph-1zene as described in JP-A-61-254626, and JP-A-65-170857.
There are those using polysiloxane in one main chain as described in Japanese Patent Publication No. These have -P-N- as the main chain.
1 or -81-0-, which is unstable in an oxidation-reduction atmosphere such as a battery.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a solid polymer electrolyte with excellent chemical or electrochemical stability, excellent productivity, and high ionic conductivity. The purpose is to

Structure of the Invention In order to achieve the objective, the present invention replaces the hydrogen of the hydroxyl group at one end of polyether diol with methoxy or ethyl
polyether μ(mu) having a reactive double bond with #I structure in which the hydrogen of the hydroxyl group at the other end is substituted with the following general formula [I] or formula [II]. ) with a reactive double bond, or a mixture of polyether/I/(mu) with a reactive double bond and a low molecular weight monomer (B) with a reactive double bond. The comb-shaped polymer obtained by the reaction contains a solvent capable of dissolving the skeleton salt and one or more salts selected from alkali metal salts, alkaline earth gold jI salts, and organic ammonium salts. This relates to a characteristic polymer solid electrolyte.

When polyether di-〃 is polyethylene oxide,
It has excellent ionic conductivity at high temperatures, but exhibits low ionic conductivity at the W edge at low temperatures.

This is thought to be because the chains of polyethylene oxide crystallize at low temperatures below room temperature, reducing the ion movement speed. The ionic conductivity is low because it is always in an amorphous state. This is thought to be because the degree of dissociation of the salt is insufficient. On the other hand, when polyether μdiode has a copolymer structure of ethylene oxide and propylene oxide, it crystallizes even at low temperatures and has excellent ionic conductivity at low temperatures below room temperature, compared to polyethylene oxide alone. In particular, when the propylene oxide ratio is set to 30 or less, the ionic conductivity increases.The hydroxyl group at one end of polyether diol μ is highly reactive and reacts with the negative electrode metal of the secondary battery, forming a solid electrolyte. This may cause deterioration. A structure in which the hydrogen of the skeleton hydroxyl group is replaced with a stable ethyl group, an ethyl group, or another 1-kiρ group (if this is done, reaction with the negative electrode metal can be prevented).

Polyether μ having a reactive double bond is obtained by reacting polyether μ diol with a halide of a group having a reactive double bond under basic conditions. The halogen of the halide is OX, Br.

commonly used. The groups having a reactive double bond are one p group, one p group, one cloth group, and one metal group. This reaction method is known as the Williamson synthesis method.
A well-known comb-shaped polymer made by reacting only polyether μ with reactive double bonds has a structure expressed by the general formula of Shimohi. The main chain and side chains of the cross-bar polymer are all stable o
-o, a-o-o bonds, and does not have active oxygen or active hydrogen. Therefore, the comb-shaped polymer is extremely stable chemically or electrochemically. Furthermore, since the skeleton comb polymer has excellent oxidation resistance and reduction resistance, it is stable against repeated charging and discharging even when used as a solid electrolyte of a secondary battery.

A chemically or electrochemically stable comb-shaped polymer can be obtained by curing only polyether μ having reactive double bonds, but curing takes a long time. More reactive monomers such as acrylic acid, methacrylic acid, methacrylic acid-methacrylate A/a methyl, acrylic acid
By mixing amide to N,N-dimethymu acrylamide, getadiene, isoprene, styrene, etc., it is possible to shorten the curing time from false to 1/1 degree.

Among the mixtures of reactive monomers, those obtained by mixing and curing getadiene or styrene are the most excellent in terms of chemical or electrochemical stability. Although the mixing ratio of the reactive monomers is not limited, a suitable range is from 10 vt% to 50 wt%. In addition, when polyethylene oxide with high crystallinity is used as a side chain, a decrease in ionic conductivity due to crystallization of the side chain can be prevented by adding a large amount of styrene. When a water-based copolymer with low crystallinity is used as a side chain, the lower the proportion of reactive monomers, the higher the ionic conductivity.Solvents that can dissolve oxygen are tetrahydrofuran, 12-methyltetrahydrofuran, 1. 3-Dioxofurne%4,4-dimethy/I/-1゜3-dioxa2% r
-Butylocton, ethylene carbonate, propylene carbonate, butylene carbonate, carbonate, 3
-Methi〃μhoon t6rt, -buti〃ete IW
, i! go -butyete, 1.2 dimethoxyV ethane, 1゜2 ethoxymethoxyethane, methoxy methoxymethane, methoxy triglyme, methoxy triglyme, ethyl μ
There are Li0I, Echi〃Jigfifu, etc. - Alkali metal salts, alkaline earth metal salts, or organic ammonium salts contained in comb-shaped polymers include Li0I
O4, Li, B]r4. L+1. Mu1116゜Li01
'5SO3, IJiP] r6. Lid, LiBr
LISONNax, Li2B100110. l1lO
F3002. NaBrNa5ON, KS (3N, M
gO14,M&'(0104)2゜(OH3)aNBF
4. (OH3)4NBr, (02H5)4NO10
4゜(02H5)4NI (03H7)4MBr,
(n-04H?)410104゜(n O+Ht)4N
Z, (n-05H11)4NI is preferred, but not limited.

The polyether having reactive double bonds may be reacted by any of the following methods: heating, irradiation with ultraviolet 1 and/or visible light, and irradiation with electron beams. In the case of the heating method, the reaction can be easily caused by adding benzybe oxide 1 azobisin butyronitrium μ as a physical reaction initiator. In addition, in the case of a method of irradiating with ultraviolet rays and/or visible light, the reaction can be easily caused by adding 1-benzoin, benzophenone, acetophenone, α-phenylacetophenone, etc. as a photoinitiator.

Example Hereinafter, the details of the present invention will be explained in more detail in Examples.

Example 1 10 parts by weight of polyethylene oxide V-ary methyl ether (ary etherification rate 98%, average molecular weight 390),
6 parts by weight of lithium perchlorate, 10 parts by weight of propylene carbonate, and 0.01 part by weight of benzophenone were uniformly mixed and dissolved. This mixture was cast on a glass plate and heated with an ultraviolet lamp of 10 times in an Agon gas stream. The film was irradiated for 8 minutes from a distance of 15 mm to obtain a 100 #ll film. The ionic conductivity of this membrane was measured using the complex impedance method and was found to be 5.5% at 25°C. It was OX 10-'S-1. Spread this film on two sheets of metal lithium foil (200p#l)'
80℃ 120μm between Q and 200μm with current density of A-
As a result of conducting an electric current test for 0 hours, no deterioration such as liquefaction of the membrane was observed, and there were no problems with practical soil.

Example Z To 10 parts by weight of polypropylene oxide V-arymethypate, A/(aryte conversion ratio 98≦1 average molecular weight 590), 6 parts by weight of lithium perchlorate and 110 parts by weight of propylene carbonate, 0 01 parts by weight of benzophenone was uniformly mixed and dissolved. This mixture was irradiated with ultraviolet light for 8 minutes in the same manner as in Example 1 to obtain a 100-voice clear film. The ionic conductivity of this membrane was measured using the complex impedance method and was found to be 4. OX 10-' 8cm
'Met. This film was subjected to the same current application test as in Example 1. As a result, no deterioration such as liquefaction of the membrane was observed, and there were no practical problems.

Example 3〃 Ethylene oxide unit and propylene oxide unit 7〃
6 parts by weight of lithium perchlorate and 10 parts by weight were added to 10 parts by weight of a random copolymer geo-〃 with a ratio of 8:2 (ary ether μ ratio 99% average molecular weight 390). Propylene carbonate and 0.01 parts by weight of benzophenone were uniformly mixed and dissolved. This mixture was irradiated with ultraviolet light for 8 minutes in the same manner as in Example 1, and
A film of pHl was obtained. The ionic conductivity of this membrane is 2
5℃ 8. OX 10-'8cya-' was shown. This film was subjected to the same current test as in Example 1. As a result, no deterioration such as liquefaction of the film was observed, and there were no practical problems.

Example 4゜Polyethylene oxide Vnnamiμmethyμade/1/(
vnnami Ete p conversion rate 98%, average molecular weight 390) 1
0 parts by weight, 6 parts by weight of lithium perchlorate, 10 parts by weight of propylene carbonate, and 0.5 parts by weight of azobisisobutyronitrium μ were uniformly mixed and dissolved. This mixture was applied to paper as in Example 1 and irradiated for 20 minutes to give 100p''
obtained the film. The ionic conductivity of this membrane was measured using the complex impedance method and was found to be 7. OX10
-'81''''Conomembrane cS*Electrification was carried out in the same manner as in Example 1. However, no deterioration such as liquefaction was observed, and there were no practical problems.

Example 5 To 7 parts by weight of polyethylene V-doyl methane ether (aluminum ether conversion rate 98%, average molecular weight 390), 3 parts by weight
Parts by weight of styrene, 10 parts by weight of propylene carbonate, 0.01 parts by weight of benzophenone, and 6 parts by weight of lithium perchlorate were uniformly mixed. This mixture was irradiated for 4 minutes in the same manner as in Example 1 to obtain a film of %100111'. The ionic conductivity of this membrane was measured using the complex impedance method and was found to be 5.0X10-'5c at 25℃.
It was ta'. This film was subjected to the same current test as in Example 1. As a result, no deterioration such as liquefaction of the membrane was observed, and there were no practical problems.

Example 6 5 parts by weight of polyethylene oxide
Parts by weight of methiμ methacrylic acid, ~10 parts by weight of propylene carbonate, 0.01 parts by weight of benzophenone,
6 parts by weight of lithium perchlorate were mixed uniformly. This mixture was irradiated for 2 minutes as in Example 1 and 10011
#I film was obtained. The ionic conductivity of this membrane was measured using the multi-strand impedance method and was found to be 4, OX at 25°C.
10-'Sew' was 0 to this membrane-1 Example 1
A similar energization theory was conducted. As a result, no deterioration such as liquefaction of the membrane was observed, and there were no practical problems.@Example 7゜Polyethylene oxide allylmethyate μ (allyate μ conversion rate rumored to be 98, average molecular weight 390) 10 parts by weight ( ，
6 parts by weight of lithium perchlorate and 10 parts by weight of propylene carbonate were uniformly mixed and dissolved. This mixture was cast on a galanu plate and placed under an accelerating voltage of 3 in an Agon air stream.
00keV s Electron beam current 10111 μm, electron dose 15
Electron beam irradiation was performed at 0 megarads to obtain a 100 p#l film. The ionic conductivity of this membrane was measured using the complex impedance method and was found to be 6.0×10−10− at 25°C.
It was 4Sc1. This film was subjected to the same current test as in Example 1. As a result, no deterioration such as liquefaction of the membrane was observed, and there were no practical problems.

Example & 10 parts by weight of polyethylene oxide V-arymethyate μ (aryte conversion rate 98%, average molecular weight 390),
6 parts by weight of lithium perchlorate, ~10 parts by weight of propylene carbonate, and 0.5 parts by weight of azobisisobutyrovitri μ were uniformly mixed and dissolved. This mixture was cast on a board and heated at 80°C for 5 hours in a nitrogen stream.
A film of 00μ tone was obtained.The ionic conductivity of this film was measured using the complex impedance method, and the result was 5.
This film was 0x10-'ac1m'.

Example 1. The soil was energized in the same manner as above, but no deterioration such as liquefaction was observed, and there were no problems with practical soil.

Example 9〈Polyethylene oxide V-aryl methyl ether μ (aryl p-ether conversion rate 98%, average molecular weight 590) 10 parts by weight (,
6 parts by weight of lithium perchlorate folate, 0.5 parts by weight of azobisisobutyronitrile, and 0.01 parts by weight of benzophenone were uniformly mixed and dissolved. This mixture was heated at 80°C in a nitrogen stream for 2 hours with stirring to remove 1 oligomer.
Obtained by adding 0 parts by weight of propylene carbonate.

This oligomer was irradiated for 4 minutes in the same manner as in Example 1,
A film of 100 p" was obtained. The ionic conductivity of this film was measured using the complex impedance method.
6. OX 10-'8cm' Te was there. This film was energized in the same manner as in Example 1, but no deterioration such as liquefaction was observed, and there were no practical problems.

Effects of the Invention As described above, the present invention can provide a bird molecule solid electrolyte with excellent chemical or electrochemical stability, excellent productivity, and high ionic conductivity. The value is extremely great @

Claims (1)

[Claims] 1) The hydrogen of the hydroxyl group at one end of the polyether diol is
Polymer having a reactive double bond, which has a structure substituted with a methyl group or an ethyl group, and the hydrogen of the hydroxyl group at the other end is substituted with the following general formula [I] or formula [II]. A comb-shaped polymer obtained by reacting an ether (A), or a comb-shaped polymer obtained by reacting a mixture of a polyether (A) having a reactive double bond and a low molecular weight monomer (B) having a reactive double bond. The polymer is an alkali metal salt,
A solid polymer electrolyte comprising one or more salts selected from alkaline earth metal salts and organic ammonium salts and a solvent capable of dissolving the salts. -CH_2-CH=CHR_1・・・・・・・・・
I] (R_1 is -H, or -CH_3, or ▲There are mathematical formulas, chemical formulas, tables, etc.▼)▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・・・・ [II] (R_2 2) The solid polymer electrolyte according to claim 1, wherein the polyether diol is polyethylene oxide. 3) The solid polymer electrolyte according to claim 1, wherein the polyether diol is polypropylene oxide. 4) The solid polymer electrolyte according to claim 1, wherein the polyether diol is a copolymer of ethylene oxide and alkylene oxide. 5) The solid polymer electrolyte according to claim 4, wherein the alkylene oxide is propylene oxide. 6) The solid polymer electrolyte according to claim 5, wherein the copolymer is a random copolymer. 7) The solid polymer electrolyte according to claim 6, wherein the molar ratio of propylene oxide is 30% or less. 8) The low molecular weight monomer is acrylic acid, methyl acrylate, methacrylic acid, methyl methacrylate, acrylamide, N,N-dimethylacrylamide, butadiene,
The solid polymer electrolyte according to claim 1, which is a compound selected from the group consisting of isoprene and styrene. 9) The solid polymer electrolyte according to claim 1, wherein A or a mixture of A and B is reacted by irradiation with ultraviolet light and/or visible light. 10) The solid polymer electrolyte according to claim 1, wherein A or a mixture of A and B are reacted by irradiation with ionizing radiation. 11) The solid polymer electrolyte according to claim 1, which is obtained by reacting A or a mixture of A and B by heating.