JPS60148003A - Ion conductive organic solid electrolyte - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an organic solid electrolyte with high ionic conductivity.

Conventionally, as a solid electrolyte having ionic conductivity, Rb
Inorganic crystals and ceramics such as Ag, I5 or stabilized zirconia are well known. On the other hand, research on solid electrolytes using organic polymers has recently become active.For example, LiCl01NaS in polypropylene oxide
It has been reported that by blending CN or KSCN, it exhibits ionic conductivity of -1 = 10 to 10 S Cm (Watanabe, Ikeda, Shinohara, Polymer
Journal, 15.85 (11383), Watanabe, Nagaoka, Kanba, Shinohara, Polymer Journal
, 14.877 (11182). ), Shikashi 1. Since polypropylene is poorly soluble or insoluble in water and its melting point (softening point) is below room temperature, it is impossible to make an electrolyte using polypropylene oxide as a polymer into a solid film or sheet, and the above-mentioned literature Among them, it is used as a solution. Further, polyacrylonitrile or polyvinylidene fluoride, which can be formed into a film or the like, is also used as a solid electrolyte, but since these are insoluble in water, they need to be dissolved in an organic solvent such as methanol. Therefore, the metal salt serving as the electrolyte must also be soluble in the organic solvent, and metal salts that are insoluble in the organic solvent cannot be used.

On the other hand, a solid electrolyte using water-soluble polyethylene oxide has been reported by P. V. Wright (Br, Polymer Journal, 7.31).
11 (1975). ), polyethylene oxide needs to have a molecular weight of several million when it is made into a film or sheet, and sticky residue remains on the film surface even after forming. P, V, and Wright use polyethylene oxide with a molecular weight of 4 million to form a pellet and use it as an electrolyte. On the other hand, it has been reported that the electrical conductivity generally decreases as a polymer with a higher molecular weight is used (Watanabe, Ikeda, Shinohara, Polymer Journal, 15, 17
5 (1983). ), Therefore, if a polyethylene oxide having a lower molecular weight, excellent film-forming ability, and no stickiness on the film surface can be found, it will be possible to improve the above-mentioned drawbacks.

As a result of extensive research in view of the above circumstances, the present inventors succeeded in obtaining a high molecular weight compound that is water-soluble and has excellent film-forming ability or sheet-forming ability, and has developed an organic solid electrolyte with high ionic conductivity. This is what we have come to offer.

That is, by reacting a polyoxyalkylene glycol with an average molecular weight of 5000 or more and an ethylene oxide unit content of 70% (wt%, the same applies hereinafter) or more with a polyhydric carboxylic acid, its anhydride, or its lower alkyl ester. This is an ionic conductive organic solid electrolyte characterized by combining the prepared high molecular weight compound having an average molecular weight of 50,000 or more with one or more metal salts of Group I and/or Group II.

The organic solid electrolyte produced in this way has excellent film-forming ability, especially elongation and tear strength, and has no stickiness on the film surface.Since the organic solid electrolyte has excellent film-forming ability, it is possible to increase the amount of metal salt distributed. becomes possible.

In the present invention, the average molecular weight of
More than 0,000 polymer compounds are produced.

It is preferable that the PO^G has an average molecular weight of 5000 or more and an ethylene oxide unit content of 70% or more. When the molecular weight is less than 5,000, the solvent solubility and film-forming ability of the polymer compound produced using it tend to be insufficient, and therefore the film of an ion-conductive organic solid electrolyte produced using the polymer compound tends to be insufficient. They also tend to lack properties, especially physical strength. On the other hand, when the ethylene oxide unit content of POAG is less than 70%, the condensation reaction when producing a high molecular weight compound by reacting POAG with a polyhydric carboxylic acid, its anhydride, or its lower alkyl ester becomes slow, and the reaction It tends to take longer, and it also becomes insoluble in water and has a lower melting point, making it difficult to solidify at room temperature.

The POAG can be obtained by addition polymerizing an alkylene oxide containing ethylene oxide to a compound having two active hydrogen atoms.

Examples of the active hydrogen group include hydroxyl groups such as water and alcohol, amino groups, and phenolic hydroxyl groups. Specific examples of the compound having two active hydrogen groups (hereinafter referred to as starting material) include water, ethylene gelcol, propylene glycol, dipropylene glycol,
．． 4-butanediol, 1,8-hexanediol, neopentyl glycol, bisphenol A, polyethylene glycol, polytetramethylene glycol, polypropylene glycol, methylamine, ethylamine,
Examples include propylamine, aniline, butylamine, octylamine, laurylamine, and cyclohexylamine.

As the alkylene oxide used for addition polymerization, ethylene oxide is used as an essential component in an amount of about 70% or more,
In addition, propylene oxide, butylene oxide, styrene oxide, etc. may be used in a total amount of about 30% or less.

When the alkylene oxides are copolymerized, block copolymerization, random copolymerization, or a combination of these may be copolymerized. Preferably.

Such addition polymerization is carried out by a conventional method, for example, using a caustic alkali such as sodium hydroxide or potassium hydroxide as a catalyst at a temperature of about 90 to 200° C. for about 2 to 30 hours.

In the present invention, the polyhydric carboxylic acids, their anhydrides, or their lower alkyl esters to be reacted with the POAG include, for example, (a) malonic acid, succinic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid; , isophthalic acid, terephthalic acid, itaconic acid, trimellidic acid, pyromellitic acid or dimer acid, (b) monomethyl ester, dimethyl ester, monoethyl ester, diethyl ester, monopropyl ester, dipropyl ester, monobutyl ester of (a) , dibutyl ester, or acid anhydrides of the acids listed in (c) and (a).

The high molecular weight compound used in the present invention can be changed by reacting the POAG with a polyhydric carboxylic acid, its anhydride, or its lower alkyl ester. For example, the POAG and a polyvalent carboxylic acid, its anhydride, or its lower alkyl ester are mixed in equal amounts in terms of the functional group ratio for esterification or transesterification, and the reaction is carried out under conditions such as 120 to 2504 °C and lO to 10 Torr. By doing so, the high molecular weight compound used in the present invention can be changed.

The average molecular weight of the high molecular weight compound is preferably 50,000 or more. When the molecular weight is less than 50,000, the ionic conductive organic solid electrolyte of the present invention produced using the high molecular weight compound has low mechanical strength and becomes brittle. - Next, the metal salts used in the present invention include metal salts of Group 1 or Group Ij, and among them, Li, Na, and K metal salts, which have a small cation radius, are preferable. These metal salts are preferably compounds having a pair of halogen ion, thiocyanate ion, or perchlorate ion as anions.

The reason why Li, Na, and metal salts with small ionic radii are preferable as cations is largely due to the structure of the polyalkylene oxide, and the cations need to be trapped in the hesox structure surrounded by ether oxygen. be.

The proportion of the metal salt used in the above high molecular weight compound is 2
% or more and 20% or less is preferable.

If it is less than 2%, the ionic conductivity will be low;
% or more, film-forming properties or sheet-forming properties tend to be poor.

Adding one or more compounds with a high dielectric constant that are effective in promoting dissociation of the electrolyte, such as dimethylformamide, ethylene carbonate, propylene carbonate, or γ-butyrolactone, to the system is recommended as long as film-forming properties are not lost. It is useful in increasing electrical conductivity.

The ion-conductive organic solid electrolyte of the present invention utilizes high ionic conductivity to prevent charging of recording paper that requires low resistance, such as electrostatic recording paper and facsimile paper, and as a diaphragm and permeable material for solid-state batteries with low self-discharge. It is thought that it will be useful in many areas such as various sensors that utilize ion selectivity, large-capacity capacitors, electrolytic application elements, display elements, etc.

Next, the ionically conductive organic solid electrolyte of the present invention will be explained based on Examples.

Production Example 1 108 parts of diethylene glycol and 20 parts of flaked caustic potassium were placed in an autoclave, and heated at 130°C to produce less than 2 kg/crrI'・G of teethylene oxide.
The reaction was carried out while gradually adding 12,000 parts. product (
The weight average molecular weight of the intermediate) was determined by measuring the hydroxyl value and alkali value and was found to be approximately 10,000.

1.8 parts of dimethyl terephthalate to 100 parts of the product obtained.
After adding 4 parts of the mixture and raising the temperature to 200°C, the mixture was reacted for 3 hours while removing methanol under a reduced pressure of I Torr to obtain a high molecular weight compound.

The obtained high molecular weight compound had a weight average molecular weight (measured by high performance liquid chromatography) of about 200,000.

Examples 1 to 5 18 parts of the high molecular weight compound obtained in Production Example 1 was added to 62 parts of distilled water.
This aqueous solution was added to 20 parts of a 10% by weight aqueous solution of LiCl0 and stirred for 2 hours at room temperature to obtain an aqueous solution containing 10.0% by weight of LiCl0 relative to the high molecular weight compound.

5g of this was placed in a Teflon petri dish with an outer diameter of 1110m+i.
It was cast, left at 50° C. for a day and night, and then dried at the same temperature under vacuum for a day and night to produce a solid electrolyte film.

After this film was left in a constant temperature and humidity chamber at 25° C. and 30% RH for 4 days, the conductivity was measured. For the measurement, a tungsten electrode and a four-terminal method Taikuun resistance measuring machine were used.

Similarly, films having the LiCl0 concentrations shown in Table 1 were prepared and measured. These results are shown in Table 1.

Production Examples 2 to 5 High molecular weight compounds shown in Table 2 were obtained in the same manner as in Production Example 1.

Examples 6 to 9 The same procedure as in Example 1 was conducted using the high molecular weight compounds obtained in Production Examples 2 to 5.

The results are shown in Table 3.

Examples 1O to 15 The same procedure as in Example 1 was carried out except that various metal salts were used in place of LiC10 in the example.

The results are shown in Table 4.

Table 4 patent applicant Dai-Kogyo Seiyaku Co., Ltd.

Claims (1)

[Claims] An average molecular weight 5 prepared by reacting a polyoxyalkylene glycol having an average molecular weight of 5,000 or more and an ethylene oxide unit content of 70% by weight or more with a polyhydric carboxylic acid, its anhydride, or its lower alkyl ester.
Group I or/and II for high molecular weight compounds of 0,000 or more
An ionic conductive organic solid electrolyte characterized by comprising one or a combination of two or more metal salts of the group A.