JP3418794B2 - Epoxy polymer solid electrolyte - Google Patents

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.

[0003]

The present invention comprises an epoxy monomer, a gelling agent, a curing accelerator, a conductivity improver, and a lithium compound as an ionic conductor, such as lithium perchlorate or lithium tetrafluoroborate. An epoxy-based polymer solid electrolyte producing composition, wherein an epoxy monomer is a compound having two glycidyl groups in one molecule; and a gelling agent has an average molecular weight of 200 to 2,0.
A polyhydric alcohol condensate in the range of 00 or a cyanoethylated polyhydric alcohol compound showing a liquid state at room temperature; a curing accelerator is an amine curing accelerator: a conductivity improver is a tetracyano compound; The present invention relates to a composition in which the lithium compound is lithium perchlorate or lithium tetrafluoroborate, and a method for producing an epoxy polymer solid electrolyte by gelling and curing the composition.

The epoxy monomer used in the composition of the present invention is a compound having two or more glycidyl groups in one molecule, for example, a bis (glycidyloxyphenyl) alkane such as bis (4'-glycidyloxyphenyl) methane. , 1,1-bis (4'-glycidyloxyphenyl) ethane or 2,2-bis (4'-glycidyloxyphenyl) propane; or 1,3-diglycidyloxy-2- (2'-cyanoethyl) oxypropane Is mentioned. The epoxy monomer may be used alone or as a mixture of two or more.

Examples of gelling agents used in the composition of the present invention include polyhydric alcohol condensates or cyanoethylated polyhydric alcohol compounds which are liquid at room temperature. As those examples, polyalkylene glycol,
Examples thereof include polyethylene glycol or polypropylene glycol, preferably polyethylene glycol, and the average molecular weight thereof is 200 to 2,000, preferably 200 to 600. Other preferable gelling agents include O, O ′, O ″ -tricyanoethyl-pentaerythritol. These gelling agents may be used alone or in combination of two or more. The weight ratio of these gelling agents to the epoxy monomer is in the range of 20 to 80% by weight, but the desired electrical characteristics of the obtained epoxy-based polymer solid electrolyte, in other words, the relative dielectric constant, In consideration of increasing the dielectric loss tangent, it is 30 to 70% by weight, preferably 40 to 60%.
It is in the range of% by weight.

The curing accelerator includes amines having one or more amino groups in one molecule, and is 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, diproprendiamine (DPDA), diethylaminopropylamine (DEAPA), hexamethylenediamine, and the like. 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. 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 and dielectric loss tangent. And the like, it is 7 to 50% by weight, preferably 10 to
It is in the range of 40% by weight.

As the conductivity improver, an electron acceptor capable of forming a charge transfer complex, especially a tetracyano compound which is a strong electron acceptor, for example, tetracyanoethylene, 7,7,
8,8-Tetracyanoquinodimethane (common name: TCNQ)
Or 1,2,4,5-tetracyanobenzene (common name:
Tetracyanobenzene) and the like. Addition of the conductivity improver increases the conductivity of the obtained epoxy-based polymer solid electrolyte. The range of addition is 1 to 8% by weight, preferably 2 to 6% by weight, based on the epoxy monomer.

Lithium compounds, such as lithium perchlorate and lithium tetrafluoroborate, function as ion conductors, and the addition amount thereof is 2 to 20% by weight, preferably 7 to 20% by weight, based on the epoxy monomer. %. Particularly, when the amount is 7 to 20% by weight, the conductivity of the obtained epoxy-based polymer solid electrolyte is as high as 10 ⁴ Ω · cm, and it can be stably obtained. Further, when the addition amount of the lithium compound, for example, lithium perchlorate or lithium tetrafluoroborate, is set to a certain amount or more with respect to the epoxy monomer, a rapid gelation reaction occurs during solid electrolyte production, which is not practical, and therefore it is preferable. Absent. This fixed amount varies depending on the type of base (epoxy monomer + gelling agent).

For example, when the epoxy monomer is bis (4-glycidyloxyphenyl) methane and the gelling agent is polyethylene glycol having an average molecular weight of about 400, it is about 10% by weight and the epoxy monomer is 1,3-.
Diglycidyloxy-2- (2'-cyanoethyl) oxypropane and when the gelling agent is O, O ', O "-tricyanoethyl-pentaerythritol, about 20
% By weight. The lithium compound such as lithium perchlorate can be added usually in a solid state, preferably in the form of fine powder, or suspended or dissolved in a suitable solvent. As a solvent for suspending or dissolving lithium perchlorate, the above-mentioned gelling agent or curing accelerator may be used, or examples thereof include methanol and ethanol.

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

Among the compositions for the epoxy-based polymer solid electrolyte described above, preferred ones are described below .

[0012] (First Example) epoxy monomers be bis (4-glycidyloxyphenyl) methane; gelator average molecular weight from 200 to 2,
Polyethylene glycol in the range of 000; the curing accelerator is meta-phenylenediamine, 4,4'-diaminodiphenyl, 4,4'-diaminodiphenylsulfone, bis (4-amino-3-ethyl-phenyl) methane or these. A mixture of two or more amines selected from
Or triethylenetetramine; a composition in which the conductivity improver is tetracyanoethylene; and the lithium compound is lithium perchlorate.

( Second Example) The epoxy monomer is 1,3-diglycidyloxy-2-
(2'-cyanoethyl) oxypropane; the gelling agent is O, O ', O "-tricyanoethyl-pentaerythritol; the curing accelerator is meta-phenylenediamine, 4,4'-diaminodiphenyl, 4, 4'-diaminodiphenyl sulfone, bis (4-amino-3-ethyl-phenyl) methane or a mixture of two or more amines selected from these, or triethylenetetramine; the conductivity improver is tetracyanoethylene. Yes; A composition wherein the lithium compound is lithium perchlorate.

Epoxy monomer: gelling agent: curing acceleration
The weight ratio of agent: conductivity improver: lithium compound is (30 to
70): (20-60): (5-50): (1-8):
A composition having a ratio of (2 to 20).

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 5 to 50% 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, 0.05 to 5 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 70 to 160 ° C., and the temperature depends on the components of the composition used and their proportions, as well as the gelling / curing time and its use. Further, the gelling / curing temperature may not be constant, and can be changed as desired. 3 times for gelation and hardening
It is from 0 to 60 minutes, depending on the components of the composition and their proportions, as well as the gelling / curing temperature and their application.
For example, when a polyethylene glycol having an average molecular weight in the range of 200 to 600 is used as the gelling agent and a modified aromatic amine is used as the curing accelerator, it is 30 to 60 minutes.

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

Next, examples of more preferable compositions will be given. Composition 1: Epoxy monomer = Epicoat 828 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd., bisphenol A type epoxy) Gelling agent = Polyethylene glycol having an average molecular weight of about 400 (manufactured by Wako Pure Chemical Industries, Ltd.) Curing acceleration Agent = Epicure 151 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd., reagent) Conductivity improver = tetracyanoethylene (manufactured by Wako Pure Chemical Industries, Ltd., reagent) Ion conductor = potassium perchlorate blending ratio ( Weight ratio) Epoxy monomer: gelling agent: curing accelerator: conductivity improver: ionic conductor = (40-60): (40-60):
(20-50) :( 1-4) :( 5-20) If desired, a conventional additive may be further added.

Composition 2: Epoxy monomer = 1,3-diglycidyloxy-2-
(2′-Cyanoethyl) oxypropane gelling agent = O, O ′, O ″ -tricyanoethyl-pentaerythritol curing accelerator = Epicure 151 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.) or triethylenetetramine Conductivity improver = tetracyanoethylene ion conductor = potassium perchlorate compounding ratio (weight ratio) Epoxy monomer: gelling agent: curing accelerator: conductivity improver: ion conductor = (30 to 70): (20 ~ 50):
(5-50): (1-4): (5-20) If desired, a conventional additive may be further added.

[0021]

The present invention will be described in more detail with reference to the following examples. The invention is not limited to these examples. Example 1 (Experimental Method) As an epoxy monomer, Epicoat 828 (registered trademark) (component is bisphenol A type epoxy, molecular weight 3)
80, epoxy equivalent 184-194 (hereinafter referred to as EP), and a polyethylene glycol having an average molecular weight of about 400 (hereinafter referred to as PE) as a gelling agent for the epoxy monomer.
G) is used as the curing accelerator, and the above-mentioned Epicure 151 (trade name), which is a kind of modified aromatic amine (hereinafter,
Amine) was used, tetracyanoethylene (hereinafter referred to as TCNE) was used as the conductivity improver, and lithium perchlorate (LiClO ₄ ) was used as the ionic conductor. L
The base resin containing iClO ₄ and TCNE is
In order to increase the dielectric constant of the epoxy polymer produced, EP
20% by weight of amine is added to 60% by weight of PEG. When TCNE is added to the base resin, TCNE is added in an amount of 2% by weight. LiClO with and without TCNE, respectively
₄ was blended in a predetermined amount to obtain a conductivity evaluation sample. These materials were sufficiently kneaded in an automatic mortar, applied on a stainless plate (thickness = 0.5 to 1 mm), degassed in vacuum, and allowed to stand at 130 ° C for 1 hour for gelation. LC for conductivity measurement
An R meter was used and the measurement frequency was 1 KHz. In addition,
The number of samples (n) was set to 5 for each formulation.

(Experimental Results and Discussion) FIG. 1 shows an example of the relationship between the conductivity of the epoxy polymer solid electrolyte with and without TCNE and the amount of LiClO ₄ compounded. In addition, FIG. 2 shows that LiClO is added to TCNE.
An example of the relation between the conductivity and the ambient temperature of 7% by weight of ₄ is shown. From Figure 1, the blended TCNE is
When the compounding amount of LiClO ₄ is around 7% by weight, 7.7 × 10 ³
It exhibits a value of about Ω · cm, and the best conductivity is obtained. On the other hand, in the case where TCNE is not blended, the conductivity tends to be improved as the blending amount of LiClO ₄ increases. However, it was found that when the content of LiClO ₄ was 10% by weight or more, rapid gelation occurred, which was not practical.
Next, from FIG. 2, it became clear that the conductivity of the sample increased with the increase of the ambient temperature and showed a certain degree of ionic conductivity.

(Summary) EP + PEG + Amine + T for the purpose of developing an epoxy polymer solid electrolyte
A study was conducted on the conductivity of a polymer gel composed of CNE + LiClO ₄ . As a result, a solid electrolyte showing relatively good ionic conductivity was obtained.

Example 2 (Raw materials and experimental method) The special epoxy monomer used in this example has the following formula:

[Table 1] 1,3-diglycidyloxy-2- (2′-cyanoethyl) oxypropane (other name: diglycidyl ether monocyanoethylated glycerin: hereinafter referred to as CN-DG). The high dielectric constant material / gelling material of CN-DG includes the following formula: HOCH ₂ C (CH ₂ OCH ₂ CH ₂ CN) ₂ O, O ′, O ″ -tricyanoethyl-pentaerythritol [alias: tri Cyanoethylated pentaerythritol (hereinafter referred to as 3CN-P)] was used.
As the curing accelerator for the solution in which 3CN-P and 3CN-P were mixed, two kinds of curing agents, triethylenetetramine (hereinafter, referred to as TETA) and the above-mentioned Epicure 151 (hereinafter, referred to as amine) which is a kind of modified aromatic amine were used. . LiClO ₄ was used as the ion conductor, and TCN was used as the conductivity improver.
E was used.

The base resin containing LiClO ₄ and TCNE is CN in the case of the CN-DG-TETA system.
-3CN to DG with 13% by weight of TETA-
A mixture of 50% by weight of P (hereinafter referred to as paint A
, And CN in the case of CN-DG-amine system
-CN to 30% by weight of amine and 3CN-P
40% by weight (hereinafter, this is referred to as paint B). The gelling condition of paint A is 100 ° C
The coating was left for 1 hour, and in the case of the coating material B, it was left for 1 hour at 130 ° C. The coating material A showed conductivity and the resistivity measured at 1 KHz was about 9.5 × 10 ⁵ Ω. Paint B
In the case of, dielectric constant was exhibited, ε _r was 27.9, and tan δ was a value around 0.16 (1 KHz).

A predetermined amount of LiClO ₄ was added to these paints, and they were sufficiently kneaded in an automatic mortar and used as samples for conductivity evaluation. The sample thus obtained is a paste-like sample,
It was applied on a stainless steel plate to a film thickness of about 0.5 to 1 mm, sufficiently defoamed in vacuum, and then gelled under the above conditions.

When TCNE is blended, both coating materials A and B are L based on the characteristics of the gelled film and the paste state.
20% by weight of iClO ₄ was blended with 2% by weight of TCNE. The method for forming the gelled film is the same as above. The performance of the obtained polymer electrolyte was evaluated from the relation between the amount of LiClO ₄ compounded and the conductivity and the temperature dependence of the conductivity. An LCR meter was used for conductivity measurement, and the measurement frequency (n) was set to 5 for each sample and evaluation.

(Experimental Results and Discussion) ・ Relationship between LiClO ₄ blending amount and conductivity of each sample FIG. 3 shows the LiClO ₄ blending amount and the volume resistivity (ρ) when LiClO ₄ was blended in the paint A and the paint B. An example of the relationship is shown. From FIG. 3, the ρ value becomes smaller and the conductivity is improved with an increase in the amount of LiClO ₄ compounded in both coating materials A and B. When the content of LiClO ₄ is 20% by weight, the coating material A,
The coating material B shows a value of about 1.4 × 10 ³ Ω · cm.

As a result of the examination, when the content of LiClO ₄ is 20% by weight or more, both the paint A and the paint B have a sharply increased viscosity in the paste state and the pot life is 3
It was shortened to about 0 minutes and the gelled film became brittle. Therefore, in the present study, when TCNE is blended to improve the conductivity, paint A is blended with 20 wt% of LiClO ₄ and TCNE is blended with 2 wt% (hereinafter referred to as sample A), and paint B is used. Was mixed with 20% by weight of LiClO ₄ and 2% by weight of TCNE (hereinafter referred to as sample B). Ρ value of sample A is 5.2 × 1
It was around 0 ² Ω · cm, and both samples showed relatively good conductivity.

Temperature Dependence of ρ Value of Each Sample FIG. 4 shows an example of the relationship between the ρ value of sample A and sample B and the ambient temperature. From FIG. 4, in both samples, the ρ value becomes smaller and the conductivity becomes higher as the temperature rises. Alternatively, when the temperature scale is graduated by the reciprocal of the absolute temperature, the ρ value changes almost linearly, and therefore it is considered that both samples show some ionic conductivity.

Frequency dependence of ρ value of each sample Here, in order to investigate the problems of polarization and dielectric property of the sample, the frequency dependence of the resistance component was measured using an impedance analyzer. FIG. 5 shows an example of the relationship between the ρ value of sample A and sample B and the measurement frequency. From Figure 5, both samples are 1
At frequencies above KHz, the ρ value shows a substantially constant value, and no significant change is observed. Also, at frequencies of 1 KHz and above, no significant change was observed in the X component. On the other hand, 1 KHz
On the low frequency side below, both ρ values of both samples are large, and the influence of polarization is observed. Large fluctuations were also seen at X minutes.

(Conclusion) For the purpose of developing an epoxy-based polymer solid electrolyte, a polymer gel based on a mixture of a cyanated epoxy monomer and a gelling agent was prepared, and the conductivity of these substances was examined. It was As a result, an ion conductive solid electrolyte having a ρ value an order of magnitude smaller than that of the epoxy polymer solid electrolyte obtained in Example 1 was obtained.

[0033]

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 compounding amount of LiClO ₄ in Example 1 and conductivity. The vertical axis represents conductivity.

2 shows the temperature dependence of conductivity of the epoxy (EP) -based polymer solid electrolyte of Example 1. FIG. The vertical axis represents conductivity.

FIG. 3 shows the relationship between the compounding amount of LiClO ₄ in Example 2 and conductivity. The vertical axis represents conductivity.

FIG. 4 shows temperature dependence of volume resistivity of each sample of Example 2. The vertical axis represents volume resistivity.

5 shows the frequency dependence of the volume resistivity of each sample of Example 2. FIG. The vertical axis represents volume resistivity.

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H01M 6/18 H01M 6/18 E 10/40 10/40 B (73) Patent holder 000003986 Nissan Chemical Industries, Ltd. Chiyoda-ku, Tokyo 3-7-1 Kanda Nishiki-cho (72) Inventor Katsumi Tanino 383 Takada, Toyama City, Toyama Prefecture Toyama Prefectural Industrial Technology Center Mechanical and Electronic Research Laboratory (72) Inventor Tomoaki Fuchi 383 Takada, Toyama City Toyama Prefecture Industrial Technology Center Mechanics and Electronics Laboratory (72) Inventor Takashi Terasawa 383 Takada, Toyama City, Toyama Prefecture Toyama Industrial Technology Center Mechanics and Electronics Laboratory (72) Inventor Shinya Orido 1-643, Kamiakae-cho, Toyama City, Toyama Prefecture Cosel Co., Ltd. (72) Inventor Yutaka Takeda 3158 Shimookubo, Osawano-cho, Kamishinagawa-gun, Toyama Prefecture Hokuriku Electric Industry Co., Ltd. (72) Inventor Hiroshi Maekawa 173-10, Naka-Okubo, Osawano-cho, Kamishinkawa-gun, Yamagata Kyoritsu Electric Works Co., Ltd. (72) Inventor Shigeru Yamada 1870, Todekoumyoji Temple, Takaoka City, Toyama Prefecture Kitamura Machinery Co., Ltd. 635 Sasakura, Machi Nissan Chemical Co., Ltd. In the Toyama factory (56) Reference JP-A-3-47833 (JP, A) JP-A-4-220469 (JP, A) JP-A-2-58526 (JP, A) JP-A-4-363869 (JP, A) JP-A-2-504399 (JP, A) US Pat. No. 4654279 (US, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01B 1/06 H01B 13/00 H01M 6/18 H01M 10/40 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. A composition for producing an epoxy-based polymer solid electrolyte comprising an epoxy monomer, a gelling agent, a curing accelerator, a conductivity improver, and a lithium compound as an ionic conductor, wherein the epoxy monomer is one It is a compound having two glycidyl groups in the molecule; the gelling agent is a polyhydric alcohol condensate having an average molecular weight in the range of 200 to 2,000, or a cyanoethylated polyhydric alcohol compound showing a liquid state at room temperature. Yes; The curing accelerator is an amine curing accelerator: The conductivity improver is a tetracyano compound; The lithium compound is lithium perchlorate or lithium tetrafluoroborate. 2. The epoxy monomer is bis (4-glycidyloxyphenyl) methane, the gelling agent is polyethylene glycol having an average molecular weight of 200 to 2,000, and the curing accelerator is meta-phenylenediamine, 4,
4'-diaminodiphenyl, 4,4'-diaminodiphenyl sulfone, bis (4-amino-3-ethyl-phenyl) methane or a mixture of two or more amines selected from these, or triethylenetetramine, The composition according to claim 1 , wherein the sex improving agent is tetracyanoethylene. 3. The epoxy monomer is 1,3-diglycidyloxy-2- (2'-cyanoethyl) oxypropane and the gelling agent is O, O ', O "-tricyanoethyl-.
Pentaerythritol, and the curing accelerator is meta-phenylenediamine, 4,4′-diaminodiphenyl, 4,
4′-diaminodiphenylsulfone, bis (4-amino-3-ethyl-phenyl) methane or a mixture of two or more amines selected from these, or triethylenetetramine, and the conductivity improver is tetracyanoethylene. 2. The composition of claim 1, which is: 4. The weight ratio of epoxy monomer: gelling agent: curing accelerator: conductivity improver: lithium compound is from 30 to 30.
70): (20-60): (5-50): (1-8):
The composition according to claim 1, which has a ratio of (2 to 20). 5. The method for producing an epoxy-based solid polymer electrolyte by heating the composition according to 70 to 160 ° C. to any one of claims 1 to 4.