JPH06267329A - Epoxy macromolecular solid electrolyte - Google Patents

Abstract

PURPOSE:To provide a highly conductive epoxy polymer solid electrolyte. CONSTITUTION:a) 1,3-diglycidyloxy-2-(2'-cyanoethyl)oxypropane, b) a product obtained by reacting metal Li with PEG of 200 to 600 average molecular weight and then removing unreacted metal Li, c) a hardening accelerator, e.g. trimethylene tetramine, and d) an ionic conductor, e.g. LiClO4, are blended together. This composition offers highly conductive epoxy polymer solid electrolyte. The electrolyte has a resistivity of 1X10<4>-2X10<2>OMEGA.cm measured at 1kHz. The electrolyte is usable as electrode material in a polymer battery.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention provides an epoxy polymer solid electrolyte having high conductivity. This solid can be used, for example, as a film-type electrode material for polymer batteries.

[0002]

2. Description of the Related Art Polymer gels such as silicon gel, acrylic gel and acrylonitrile gel are used as polymer materials used for polymer solid electrolytes, and perchlorate is used as ion conductor. Lithium acid (LiCl
O ₄ ) or lithium tetrafluoroborate (LiBF
₄ ) is used. However, nothing has been found that can be put to practical use. Furthermore, there are reports of compounds containing an ion conductor with general-purpose epoxy polyethylene glycol (hereinafter referred to as PEG) and compounds containing a high dielectric constant special epoxy compound with an ion conductor (Tanino et al. Molecular Solid Electrolyte (I) ", H4 Society of Electrical Engineers of Japan Hokuriku University, Abstracts D-16; Tanino et al .:" Epoxy Polymer Solid Electrolyte (I) ", H4 Society of Electrical Engineers of Japan Hokuriku University, Abstracts D -17).

[0003]

The present invention provides a) 1,3-
Diglycidyloxy-2- (2'-cyanoethyl) oxypropane, b) PEG having an average molecular weight of 200 to 600 and metal L
A product obtained by removing unreacted metallic Li after reacting i (hereinafter referred to as LiPEG), c) a curing accelerator, and d) an ionic conductor. And a composition for producing a solid polymer electrolyte.

1,3-Diglycidyloxy-2- (2'-cyanoethyl) oxypropane (hereinafter referred to as CN-DG) used in the composition of the present invention has the following formula:

[Table 1] Is a compound represented by.

The average molecular weight of PEG used in the synthesis of the epoxy polymer solid electrolyte of the present invention is generally 20.
It is from 0 to 600, particularly preferably from 300 to 400.

The metallic Li used in the production of the LiPEG of the present invention is preferably in the form of particles having a particle size such that the reaction with PEG proceeds smoothly, and the usual particle size is 1 to 4 mm,
It is preferably 1 to 2 mm. The granular Li is suspended in an inert organic medium and is usually a liquid aliphatic or aromatic hydrocarbon such as paraffin, ligroin, xylenes, toluene and the like. It must be a solvent that can be easily removed when removing excess metal Li. The weight ratio of Li to PEG for producing the LiPEG of the present invention varies depending on the molecular weight of PEG, but is usually in the range of 0.8 to 4%, in other words, usually equimolar to 1/2 mol per PEG mol. Is the range.

To prepare the LiPEG of the present invention, P
The temperature for reacting EG with Li is usually room temperature to 90 ° C.
And preferably 50 to 70 ° C. The reaction of Li is preferably carried out under an anhydrous and inert atmosphere, and is usually carried out under an atmosphere of an inert gas such as nitrogen or helium or under a reduced pressure of about 1 Torr.

[0008] As the amount of LiPEG compounded in CN-DG increases, there is a preferable tendency that the electroconductivity of the obtained gel product increases, but the amount of LiPEG compounded is P.
If 120 parts by weight or more with respect to 100 parts by weight of EG, the gelled film becomes brittle, and if 160 parts by weight or more, a gelled film cannot be obtained. Therefore, 55% by weight or less from the practical viewpoint,
It is particularly preferably in the range of 30 to 50% by weight.

As the curing accelerator, there is an amine having one or more amino groups in one molecule, and a commonly used amine-based curing agent for epoxy, for example, (multi)
Examples thereof include alkylene polyamines or aromatic amines, and examples thereof include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diproprenediamine (DPDA), diethylaminopropylamine (DEAPA), hexamethylenediamine, and other linear chains. Aliphatic amines; Mensendiamine, isophoronediamine, bis (4-amino-3-methylcyclohexyl) methane, bis (4-aminocyclohexyl)
Methane, 2,6-bis (aminomethyl) cyclohexane, N- (aminoethyl) -piperazine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro (5,5) Cyclic amines such as undecane, meta-xylenediamine, meta-phenylenediamine, 4,
Aromatic amines such as 4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone and bis (4'-amino-3-ethylphenyl) methane. These curing accelerators may be used alone or in combination of two or more. Of these curing accelerators, the preferred ones are polyalkylene polyamines such as triethylene tetramine. The weight ratio of this curing accelerator to the epoxy monomer is in the range of 5 to 50% by weight, but desired electrical characteristics of the obtained epoxy-based polymer solid electrolyte, in other words, relative permittivity, dielectric loss tangent And the like, it is 10 to 40% by weight, preferably 1
It is in the range of 0 to 30% by weight. The amount of the curing accelerator added tends to decrease as the number of NHs per unit weight of the curing accelerator increases. When the curing accelerator is triethylenetetramine, it is usually in the range of 5 to 18% by weight, preferably 10 to 15% by weight, based on CN-DG mixed with a predetermined amount of LiPEG.

Lithium compounds such as lithium perchlorate and lithium tetrafluoroborate function as ionic conductors, and the addition amount thereof is required to maximize the conductivity of the obtained epoxy polymer solid electrolyte. , Too much is not preferable, for example, "CN-DG and LiPEG
With 100 parts by weight of the mixture of
The amount of O ₄ added is generally 5 to 20 parts by weight, preferably 5 to 15 parts by weight, particularly 5 to 10 parts by weight. The lithium compound to be added is preferably lithium perchlorate.

The ionic conductor was dissolved in an inert organic solvent capable of dissolving the ionic conductor, for example, propylene carbonate, and then added to CN-DG in a blend of PEG and a curing accelerator. The weight ratio of ionic conductor to propylene carbonate is usually about 1: 1 to 3, although propylene carbonate is usually used in an amount sufficient to dissolve the ionic conductor.

If desired, conventional additives such as light stabilizers and heat stabilizers may be added to the composition of the present invention.

Among the above-mentioned compositions for producing an epoxy polymer solid electrolyte, preferred ones are described below. (First example) The weight ratio of CN-DG: LiPEG: triethylenetetramine: lithium compound is (3-7) :( 7-
3) A composition having a ratio of (1 to 1.5): (0.5 to 2).

(Second Example) LiPEG has an average molecular weight of about 40.
0 is PEG-derived LiPEG; the curing accelerator is triethylenetetramine: the lithium compound is lithium perchlorate, and the weight ratio of each component is CN-DG: LiP.
EG: triethylenetetramine: lithium compound ((3
~ 7): (7-3): (1-1.5): (0.5-2)
The composition is a ratio of.

In order to mix the components of the composition for the above-mentioned epoxy polymer solid electrolyte, a conventional method may be used,
The mixing temperature is a temperature at which gelation of the epoxy monomer does not start, for example, 10 to 40 ° C. Thus, the obtained composition is gelled / cured immediately after production, or is stored until gelled / cured for convenience of the process. The storage temperature in this case is generally 20 ° C. or lower.
Thus, when the obtained epoxy-based polymer solid electrolyte composition is gelled and cured, a curing accelerator other than the above is added, if necessary. Examples of this curing accelerator are:
Any of the above epoxy curing accelerators may be used. The amount added is in the range of 0 to 20% by weight with respect to the composition of the present invention.

The properties of the composition of the present invention when it is gelled and cured are liquid or solid, but it is preferably liquid, and if desired, it is heated and melted to form a liquid. This composition is applied onto a target substrate (for example, a stainless steel plate or a stainless steel electrode) or put in a casting mold to be gelated and cured. When it is applied on a substrate, it is applied so that the thickness after gelling and curing is a desired thickness, for example, 0.1 to 1 mm. Prior to gelation / curing, in order to remove air bubbles in the composition and a solvent optionally added as a solvent for lithium perchlorate, defoaming is performed under reduced pressure, and a volatile solvent is optionally evaporated.

The gelling / curing temperature is from room temperature to 60 ° C., and the temperature depends on the components of the composition to be used and the proportion thereof, and the gelling / curing time and its use. Further, the gelling / curing temperature may not be constant, and can be changed as desired. 1 time for gelation and hardening
~ 10 hours. The time depends on the components of the composition and their proportions, as well as the gelling / curing temperature and their use.

Thus, the obtained epoxy polymer solid electrolyte has a high electrical conductivity which is an electrical characteristic, and its volume resistivity is 1 × 10 ⁴ to 2 × 10 ² Ω · cm.

[0019]

The present invention will be described in more detail with reference to the following examples. The invention is not limited to these examples. Example: (Experimental method) The reaction product of PEG and Li was obtained by blending metal Li (granular) with PEG having an average molecular weight of about 400.
The reaction was performed in a vacuum at a temperature of about 70 ° C. and 1 Torr, and after completion of the reaction, residual Li was removed to obtain the product (hereinafter, this product is abbreviated as LiPEG). A reaction promoter of 1,3-diglycidyloxy-2- (2′-cyanoethyl) oxypropane (see the above chemical formula, hereinafter, referred to as CN-DG) and LiPEG is triethylenetetramine (hereinafter, referred to as TETA). .), "CN-DG and L
The blending amount of TETA in 100 parts by weight of a predetermined amount of iPEG and TETA was always 13 parts by weight. Two types of ion conductors, LiClO ₄ and LiBF ₄ , were used as the ionic conductors to be added to these epoxy reaction products.

A predetermined amount of the ionic conductor was dissolved in propylene carbonate and then blended in the epoxy resin. At this time, the mixing ratio of the ionic conductor and propylene carbonate was 1: 1 by weight. The gelling conditions of the composition containing no ionic conductor and the composition containing the ionic conductor are as follows:
It was allowed to stand for 0 hour. These epoxy-based epoxy-based polymer solid electrolytes have a film thickness of 0.5 on a stainless steel plate.
It was formed to be about 1 mm. The performance of the solid polymer electrolyte membrane thus obtained was evaluated from the relationship between the blending amount of each material and the conductivity, and the temperature dependence and frequency dependence of the conductivity. An impedance analyzer is used for conductivity measurement, and the measurement frequency is 5 Hz to 10 MH
z. The number of samples (n) is 5 for the samples and the evaluation.
And

(Experimental Results and Discussion) (1) LiPEG Blending Amount and Volume Resistivity (ρ) FIG. 1 shows a gelled membrane in which LiPEG is blended with CN-DG,
An example of the relationship between the amount of LiPEG and ρ is shown. From Figure 1,
As the amount of LiPEG added increases, the ρ value decreases almost proportionally, and the conductivity improves. When the LiPEG content is 0% by weight, the ρ value is around 4.9 × 10 ⁸ Ω · cm (ε
_r is around 27), 50 wt% (CN-DG: LiPEG
= 50:50 (w: w)) 1.5 × 10 ⁵ Ω · cm
Before and after and 60% by weight (CN-DG: LiPEG = 4
At 0:60 (w: w)), a value around 8.0 × 10 ⁴ Ω · cm is shown. However, when the content of LiPEG was 60% by weight, the gelled film was considerably brittle and 70% by weight (CN-DG: Li).
No gelled film was obtained with PEG = 30: 70 (w: w)). Therefore, when compounding the ionic conductor, C
A mixture of N-DG: LiPEG in a weight ratio of 50:50 was adopted (hereinafter, this kind of mixture is abbreviated as sample A).

(2) Relationship between Ion Conductor Blending Amount and ρ Value FIG. 2 shows an example of the relationship between the ionic conductor and the ρ value in the gelled film in which the ionic conductor is mixed with the sample A. From FIG. 2, Li
The conductivity of both ClO ₄ and LiBF ₄ was the best when the blending amount was around 10 wt%, and the ρ value at the LiClO ₄ blending amount of 10 wt% based on the total weight of the blend was 4.0 ×.
The ρ value at about 10 ² Ω · cm and the LiBF ₄ content of 10% by weight is about 2.2 × 10 ³ Ω · cm. It should be noted that no gel film was obtained with any of the ionic conductors when the content was 30% by weight.

When LiClO ₄ is blended, the conductivity is obviously good. Therefore, in order to evaluate the temperature dependence and frequency dependence of the ρ value of this type of solid polymer electrolyte, a study was made on a sample A containing 10% by weight of LiClO ₄ (hereinafter, this sample is a sample). (Abbreviated as B).

(3) Temperature Dependence of ρ Value of Sample B FIG. 3 shows an example of temperature characteristics of ρ value of sample B. From FIG. 3, it can be inferred that Sample B is an ionic conductor because the ρ value decreases with increasing temperature. Also, 140 ℃
It is inferred that the tendency that the ρ value again becomes large due to the evaporation of propylene carbonate depending on the sample B. (4) Frequency Dependence of ρ Value of Sample B FIG. 4 shows an example of frequency characteristics of ρ value of sample B. From FIG. 4, the ρ value of the sample B is relatively unaffected by the frequency, and particularly shows a substantially constant value between 1 KHz and 1 MHZ.

[0025]

EFFECT OF THE INVENTION By gelling and curing the composition of the present invention, a highly conductive epoxy polymer solid electrolyte is obtained, which is useful as a polymer conductive film as an electrode material for polymer batteries. This contributes to higher performance and higher functionality of the polymer battery.

[Brief description of drawings]

FIG. 1 shows the relationship between the blending amount of LiPEG in a blend of PEG and LiPEG and the volume resistivity (ρ) of the obtained epoxy polymer solid electrolyte.

[FIG. 2] “Blend of PEG 50 parts by weight and LiPEG 50 parts by weight (Sample A), blend of triethylenetetramine and ionic conductor” Ion conductor compounding amount in 100% by weight, and the obtained epoxy polymer The relationship of the volume resistivity (ρ) of the solid electrolyte is shown.

FIG. 3: “50 parts by weight of PEG and 50 parts by weight of LiPEG (Sample A), triethylenetetramine and LiCl.
Compounding of O ₄ "LiClO ₄ compounding amount in 100% by weight 1
The temperature dependence of the ρ value of 0% by weight (Sample B) is shown.

FIG. 4: “50 parts by weight of PEG and 50 parts by weight of LiPEG (Sample A), triethylenetetramine and LiCl.
Compounding of O ₄ "LiClO ₄ compounding amount in 100% by weight 1
The frequency dependence of the ρ value of 0% by weight (Sample B) is shown.

[Explanation of symbols]

n = 5 indicates that the number of samples for each sample and evaluation is 5.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 000104537 Kitamura Machinery Co., Ltd. 1870 Todekomyoji, Takaoka, Toyama Prefecture (71) Applicant 000003986 Nissan Chemical Co., Ltd. 3-7 1 Kandanishikicho, Chiyoda-ku, Tokyo (72) Inventor Katsumi Yano, 383 Takada, Toyama City, Toyama Prefecture, Tochigi Industrial Technology Center, Mechanical and Electronic Research Laboratory (72) Inventor, Tomoaki Futaku, 383, Takada, Toyama City, Toyama Prefecture, Toyama Industrial Technology Center, Mechanical and Electronic Laboratory (72) Invention Takashi Terasawa, 383 Takada, Toyama City, Toyama Prefecture, Tochigi Industrial Technology Center, Mechanics and Electronics Laboratory (72) Inventor Shinya Orito 78, Gengenji, Tateyama-machi, Nakashinkawa-gun, Toyama Prefecture Cosel Corporation, Tateyama Factory (72) Invention Yutaka Takeda 3158 Shimookubo, Osawano-cho, Kamishinkawa-gun, Toyama Prefecture Hokuriku Electric Industry Co., Ltd. (72) Inventor Hiroshi Maekawa 173-10 Naka-Okubo, Osawano-cho, Kamishinagawa-gun, Toyama Prefecture Kyoritsu Electric Works Co., Ltd. (72) Inventor Shigeru Yamada 1870 Tode Komyoji Temple, Takaoka City, Toyama Prefecture Kitamura Machinery Co., Ltd. (72) Inventor Shinsuke Yagi 635 Sasakura, Fuchu-cho, Nenju-gun, Toyama Prefecture Inside Nissan Chemical Co., Ltd. Toyama Plant

Claims (6)

[Claims] 1. a) 1,3-Diglycidyloxy-2-
(2'-cyanoethyl) oxypropane (hereinafter, referred to as CN-
It is called DG. ), B) PEG having an average molecular weight of 200 to 600 and metal L
A product obtained by removing unreacted metallic Li after reacting i (hereinafter referred to as LiPEG), c) a curing accelerator, and d) an ionic conductor. And a composition for producing a polymer solid electrolyte. 2. The composition for producing a polymer solid electrolyte according to claim 1, wherein the curing accelerator is triethylenetetramine. 3. The composition for producing a polymer solid electrolyte according to claim 1, wherein the PEG has an average molecular weight of 200 to 600. 4. The composition for producing a polymer solid electrolyte according to claim 1, wherein the ionic conductor is lithium tetrafluoroborate or lithium perchlorate. 5. Triethylenetetramine: CN-DG: L
The weight ratio of iPEG: lithium tetrafluoroborate is
The composition for producing a solid polymer electrolyte according to any one of claims 1 to 4, wherein the composition is 1 to 1.5: 3 to 7: 7 to 3: 0.5 to 2. 6. Triethylenetetramine: CN-DG: L
The weight ratio of iPEG: lithium perchlorate is 1 to 1.5:
The composition for producing a polymer solid electrolyte according to any one of claims 1 to 4, wherein the composition is 3 to 7: 7 to 3: 0.5 to 2.