JPH10134635A - Organic solid electrolyte - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolyte having large ionic conductivity and a good film forming property and excellent in flexibility and resiliency by cross linking reaction a composition containing a specific compound into a gelatinous material. SOLUTION: A composition containing a compound expressed by the formula is cross linking reacted to obtain a gelatinous material, where R<1> indicates hydrogen atom or the methyl group, and R<2> , R<3> independently indicate hydrogen atom or an alkyl group or hydroxy methyl group having the carbon number of 1-4. A compound having a low molecular weight and an unsaturated functional group such as acrylic amide and its derivative, for example, is used for the compound expressed by the formula. Methacrylic amide and N-methylol acrylic amide are used as the example for acrylic amide and its derivative. A polymer is formed by the acrylic amide compound, the whole composition is made flexible, and an electrolyte having a good film forming property and excellent in flexibility and resiliency is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for providing an organic electrolyte useful for high energy density batteries, electrochromic devices, and the like. For more information,
High ionic conductivity, excellent thin film formation, flexibility,
The present invention relates to an organic solid electrolyte having excellent elasticity.

[0002]

2. Description of the Related Art In general, inorganic solid electrolytes and organic electrolytes are known as electrolytes applicable to high energy density batteries, electrochromic devices and the like. Inorganic solid electrolytes are excellent in that they have high ionic conductivity, but have problems in that thinning is difficult and cracks are liable to occur.

On the other hand, a liquid electrolyte obtained by dissolving an alkali metal salt in a glycol polar solvent such as a low molecular weight polyalkylene glycol is known as an organic electrolyte, and is excellent in that it has a high ionic conductivity. There are problems such as liquid leakage at the peripheral seal. Also, in the case of an electrochromic device, when the glass surface or the like sandwiching the electrolyte layer is vertical, the lower part swells due to the hydrostatic pressure of the electrolyte, and as a result, the whole becomes non-uniform. There is a disadvantage that it becomes difficult.

[0004] Even when the polyalkylene glycol has a molecular weight of 10,000 or more, it becomes a solid and the problem of liquid leakage disappears, but the ionic conductivity decreases.

As described above, from the viewpoint of conductivity, those having a small molecular weight are suitable, but those having a small molecular weight have a problem because they are liquids as described above.

As a method for solving this problem, it is conceivable to solidify low-molecular-weight glycols using, for example, a polyfunctional isocyanate compound. descend.

Also, US Pat. No. 4,908,283 discloses that acrylates of polyethylene glycol are polymerized. In this case, too, the polymer is entirely polymerized so that the elasticity is reduced. It will be missing.

As another solution, it is conceivable to construct a gel-like substance by using a polyfunctional monomer and to hold a low molecular weight glycol-based compound in the gel-like substance. Since it is not stably present in the gel and separates for a long period of time, durability becomes a problem.

[0009]

DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned problems of the prior art, and maintains a glycol compound having a low molecular weight and a high electric conductivity in a stable gel-like material to obtain a solid. However, an object of the present invention is to provide an organic solid electrolyte having high ionic conductivity, good film formability, and excellent flexibility and elasticity.

[0010]

SUMMARY OF THE INVENTION The present invention is to solve such a problem, and the means for solving the problem is represented by the following general formula (A):

Embedded image (Wherein R ¹ represents a hydrogen atom or a methyl group; R ² ,
R ³ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a hydroxymethyl group. A) a gel-like substance obtained by subjecting a composition containing the compound represented by the above) to a crosslinking reaction.

In this gel composition, the following general formula (B)

Embedded image (Wherein R ⁴ represents a hydrogen atom or a methyl group, k and l each represent an integer of 0 to 50, and k + 1 is 5 to 50)
It is. ), An aprotic solvent, and inorganic salts.

Further, instead of the compound of the above general formula (B), a compound of the general formula (C)

Embedded image (In the formula, R ⁵ represents a hydrogen atom or a methyl group.)

Further, it is possible to contain all of the compound of the general formula (B), the compound of the general formula (C), and the aprotic solvent.

Examples of the compound of the general formula (A) include compounds having a low molecular weight and an unsaturated functional group such as acrylamide and derivatives thereof.

Examples of acrylamide and its derivatives include acrylamide and methacrylamide, as well as N-methylolacrylamide and N-methylolmethacrylamide.

Examples of the compound of the formula (B) include alkylene glycol acrylates and methacrylates having a molecular weight of 200 to 2,000.

Examples of alkylene glycol acrylate compounds having a molecular weight of 200 to 2000 include acrylates or methacrylates of polyethylene glycol having a molecular weight of 200 to 2,000, and molecular weights of 200 to 200.
And acrylates and methacrylates of polypropylene glycol having a molecular weight of 0 or a co-adduct of ethylene oxide and propylene oxide having a molecular weight of 200 to 2,000.

Further, the compound of the general formula (C) includes
Glycidyl acrylate and glycidyl methacrylate are exemplified.

Further, as the aprotic solvent, the following general formula (D)

Embedded image (Wherein R ⁶ and R ⁷ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
Represents an integer of 50, and i + j is 1 to 50. ), Olefin carbonates, γ-butyrolactone, or 1,2-dimethoxyethane.

In this case, examples of the compound of the formula (D) include an alkylene glycol having a molecular weight of 2000 or less and an alkyl ether thereof.

Examples of the glycol compound include polyethylene glycol, polypropylene glycol, a co-adduct of ethylene oxide and propylene oxide, and a molecular weight of 2,000 or less is particularly preferable. In addition to such a polymer, it is also possible to use ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and the like.

Examples of the olefin carbonates include propylene carbonate and ethylene carbonate.

Further, as the inorganic salts, LiCl, Li
Br, LiI, LiSCN, LiBF ₄ , LiAs ₆ ,
LiAsF ₆ , LiClO ₄ , KSCN, NaSCN and the like.

The compounds in each of these groups may be selected and used one by one, or the properties of the gel-like substance may be changed by selecting and using a plurality of substances in the same group.

The composition ratio of these substances is not particularly limited.
It may be determined according to the properties of the target gel, but usually, the acrylamide compound is 10 to 70% by weight,
Alkylene glycol acrylate and glycidyl acrylate compounds having a molecular weight of 200 to 2,000 are 10
-50% by weight, 20-80% by weight of glycol compound and 1-30% by weight of alkyl metal salt.

Further, it is also possible to use a substance other than the above in combination for improving the gel properties and the electric conductivity.

Examples of the means for causing a crosslinking reaction include heating, ultraviolet irradiation, and electron beam irradiation.

In the present invention, since a polymer is formed by a compound having a low molecular weight and an unsaturated functional group such as acrylamide and a derivative thereof, the whole composition becomes flexible and has good film-forming properties. A solid substance having excellent flexibility and elasticity is formed.

Further, the polymer has a molecular weight of 200 to 2
When an alkylene glycol acrylate compound or glycidyl acrylate compound having a molecular weight of 2,000 is copolymerized, a glycol group or a glycidyl group is fixed, and the fixed glycol group or the like is conjugated with an alkylene glycol having a molecular weight of 2000 or less or an alkyl ether thereof. In this way, a stable gel is formed.

In this case, an organic solid electrolyte having a high ionic conductivity is formed by dissolving the inorganic salts since the alkylene glycol has a relatively low molecular weight.

Furthermore, since the components forming the solid electrolyte are composed of three components, the properties such as film-forming properties, flexibility and elasticity can be freely changed by changing the ratio of the components. It is in. Even though a solid electrolyte is used, the required properties vary depending on the purpose of use. Therefore, it is very convenient to obtain a large degree of freedom in the properties obtained in designing the electrolyte.

In the case of gelation by heating and irradiation with ultraviolet light, it is preferable to add a polymerization initiator such as azobisisobutyronitrile or benzoin ethyl ether, and to add a polymerization inhibitor at the compound preparation stage. It is also preferable to keep it.

In the production of an electrochromic device or the like, the liquid of the compound mixture before gelation can be introduced into the electrolyte enclosing portion, and then gelled by any of the above means. It is also possible to attach a gel-like sheet to an electrode surface or the like.

[0034]

Embodiments of the present invention will be described below. <Example 1> N-methylol methacrylamide 15 parts Glycidyl methacrylate 10 parts Polyethylene glycol 600 30 parts Lithium perchlorate 10 parts After mixing and dissolving the above components, azobisisobutyronitrile was added, and the mixture was heated to 80 ° C. Thus, a gel-like substance was obtained. The obtained gel-like substance was in the form of an elastic transparent gel, was stable in shape, and even if left as it was for one week, separation of polyethylene glycol was not observed. The conductivity is 1.6
× 10 ⁻⁴ S / cm was good.

<Example 2> Acrylamide 10 parts Polyethylene glycol monomethacrylate 15 parts Polyethylene glycol 200 30 parts Potassium thiocyanate 1 part After mixing and dissolving the above components, azobisisobutyronitrile was added, and the mixture was heated to 80 ° C. Thus, a gel-like substance was obtained. The shape of the obtained gel-like substance is stable, flexible, rich in elasticity,
Even if left as it is for one week, separation of polyethylene glycol was not observed. The conductivity is 1.6 × 1
It was good at 0 ^-5 S / cm.

Example 3 N-methylolacrylamide 25 parts Glycidyl methacrylate 15 parts Diethylene glycol dimethyl ether 30 parts Potassium thiocyanate 3 parts After mixing and dissolving the above components, azobisisobutyronitrile was added, and the mixture was heated to 80 ° C. Thus, a gel-like substance was obtained. The shape of the obtained gel-like substance is stable, flexible, rich in elasticity,
Even if left for one week, separation of diethylene glycol dimethyl ether was not observed.

<Comparative Example 1> N-methylol methacrylamide 10 parts Polyethylene glycol 200 30 parts Potassium thiocyanate 3 parts After mixing and dissolving the above components, the mixture was heated to 80 ° C, but only a viscous fluid was obtained. And did not gel.

<Comparative Example 2> N-methylol methacrylamide 10 parts Phenyl glycidyl ether 15 parts Polyethylene glycol 200 30 parts Potassium thiocyanate 1 part After mixing and dissolving the above components, the mixture was heated to 80 ° C. Only a fluid was obtained, and although partly gelled, separation of polyethylene glycol 200 was observed.

Comparative Example 3 Polyethylene glycol 10000 100 parts Lithium perchlorate 10 parts The above components were mixed and dissolved, but the conductivity was 1.6 ×
It was 10 ^-7 S / cm.

[0040]

As described above, according to the present invention, a glycol compound having a low molecular weight and a relatively high conductivity is contained in a gel-like structure formed of a polymer of an unsaturated compound having a small molecular weight. An organic material that can be stably retained, has further improved conductivity by adding an inorganic salt, is useful for high energy density batteries and electrochromic devices, and has excellent film-forming properties, flexibility and elasticity. A solid electrolyte can be easily obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 6/22 H01M 6/22 C 10/40 10/40

Claims (4)

[Claims] 1. The following general formula (A): (Wherein R ¹ represents a hydrogen atom or a methyl group; R ² ,
R ³ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a hydroxymethyl group. An organic solid electrolyte, which is a gel-like substance obtained by subjecting a composition containing the compound represented by the above) to a crosslinking reaction. 2. The composition to be gelled by a crosslinking reaction contains the following general formula (B): (Wherein R ⁴ represents a hydrogen atom or a methyl group, k and l each represent an integer of 0 to 50, and k + 1 is 5 to 50)
It is. 2. The organic solid electrolyte according to claim 1, comprising a compound represented by the formula (1), an aprotic solvent, and inorganic salts. 3. The composition to be gelled by a crosslinking reaction contains the following general formula (C): (Wherein R ⁵ represents a hydrogen atom or a methyl group.) The compound represented by the aprotic solvent and inorganic salts, which are contained claims 1 organic solid electrolyte according. 4. The aprotic solvent represented by the following general formula (D): (Wherein R ⁶ and R ⁷ each independently represent a hydrogen atom, a methyl group, or an ethyl group;
Represents an integer of 50, and i + j is 1 to 50. 4. The organic solid electrolyte according to claim 2, which is a compound represented by the formula (1), olefin carbonates, γ-butyrolactone or 1,2-dimethoxyethane.