JPH0238451A - Ionically conductive solid electrolyte material - Google Patents

Abstract

PURPOSE:To obtain the title material having sufficient ionic conductivity at or near room temperature and having an improved ionic conductivity by mixing a specified polymeric matrix with an ionic compound. CONSTITUTION:A polyglycerol (a) of an average degree of polymerization or condensation >=3 and a kinematic viscosity v at 50 deg.C>=1000cSt is reacted with a polyether (b) which is an ethylene oxide homopolymer or a random or sequential copolymer (b) of ethylene oxide with an alkylene oxide of the formula [wherein R is a (halogenated) alkyl, alkenyl or alkoxy] and has 5-2000 repeating ethylene oxide units at 50-200 deg.C under a pressure <=10kg/cm<2> in the presence of an alkali catalyst, and the obtained addition polymer composed of a main chain comprising component (a) and side chains comprising component (b) is crosslinked to obtain a polymeric matrix (A) comprising a three-dimensional crosslinked product. Component A is reacted with an ionic compound (B) (e.g., lithium perchlorate) in an oxygen to ionic metal ratio of 5-100:1.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention relates to an ion-conductive polymer solid electrolyte that is expected to have a wide range of applications in batteries, electrochromic devices, electrostatic needles, large-capacity electrolytic capacitors, sensors, etc. be.

[Background Art] In recent years, the electronics industry has made remarkable progress, and technology for increasing the speed and density of electronic elements is rapidly progressing, creating a demand for high-performance and highly reliable electronics materials.

Solid electrolytes that have been reported in recent years can be roughly divided into inorganic solid electrolytes and polymer solid electrolytes. Although the ionic conductivity of polymeric solid electrolytes is much lower than that of inorganic solid electrolytes (10-'S/cm), it has good formability and flexibility that allows it to be made thinner and larger in area. Since they are superior in terms of performance and other properties, much research and development has been conducted on polymer-based solid electrolytes.

In particular, since 1975, when M., B., Armand et al. announced their attempt to use a solid electrolyte prepared by dissolving various alkali metal salts in polyethylene oxide in an all-solid-state secondary battery, much research has been conducted on polymeric solid electrolytes. and suggestions have been made.

For example, a solid electrolyte in which polyethylene oxide is dissolved in a maleic acid or methacrylic acid polymer gel (ionic conductivity at room temperature: approximately 10-55/cm) (DR, Pa
yne et al, Polymer, 23.690
[1982); ETsuchida et al.
5olid 5tate Ionics, 11.2
27+19831), a solid electrolyte (ionic conductivity, 350C
1.94x 1O-6S/cm) (S, Kohji
ya et al, PolymerPreprint
s Japan, 35.778 (19861),
A solid electrolyte made by doping a diisocyanate crosslinked polymer of triol-type polyethylene oxide or triol-type propylene oxide with metal salts (ionic conductivity = 30°
1O-5S/cm in C) (M, Watanabe e
tal, 5solidState Ionics,
18 & 19.338 (19861, Japanese Patent Publication No. 6248
No. 716), an easily polymerizable phosphoric acid divinyl monomer having one or two oligooxyethylene chains per unit, or a mixture of a vinyl monomer and an alkali metal salt (ionic conductivity: 10-' at 25°C) S/cm) (A, Ya
mada et al, Polymer Pr
eprints Japan34.903 (198
5), JP-A-61-260557 and JP-A-61
-254613 Publication (Polymethacrylic acid oligooxyethylene/methacrylic acid alkali metal salt copolymer counterion fixed solid electrolyte (ionic conductivity 1O-7 at Murotaki)
S/cm) (Polymer Reprints J
apan.

35.583+1986+1, an ionically conductive polymer composite consisting of polyalkylene carbonate, an inorganic salt, and an organic solvent that dissolves the inorganic salt (ionic conductivity: 6×10−
'S/am) (Japanese Unexamined Patent Publication No. 62-30147) and an ionic conductive material consisting of an aliphatic epoxy resin with an epoxy equivalent of 80 to 200, cyclic ethers, cyclic esters, cyclic amides, furans, and an epoxy curing agent. Crosslinked resin composition (ionic conductivity: 10-'S/cm at room temperature) (
Japanese Patent Publication No. 63-6573) has been proposed. However, all of these solid electrolytes had low ionic conductivity and were not satisfactory.

On the other hand, polymers containing ethylene oxide tend to form crystalline structures at temperatures clearly higher than room temperature, and as a result, conductivity rapidly decreases at low temperatures. There are many proposals aimed at improving this drawback.

For example, JP-A-59-18284 states that a copolymer of ethylene oxide and cyclic ether containing an ionic compound does not crystallize at room temperature, which is the operating temperature, and its ionic conductivity is 10-' at 45°C. S/cm, and JP-A-59-182844 also proposes a polymer material containing ethylene oxide, a substituted or unsubstituted cyclic ether with four or more rings, and an ionic compound. .

Furthermore, JP-A No. 61-83249 discloses a polymer material in which polypropylene oxide or methoxyglycidyl ether is randomly distributed inside polyethylene oxide to dissolve an ionic compound, and the ionic conductivity of the material is 47. 10-'S/cm at °C.

In addition, when a battery is constructed using a solid electrolyte, the terminal -OH of the polymer matrix reacts with Li, which is the electrode, so the -OH can be blocked and the mechanical properties and crystallization behavior of the solid electrolyte can be improved. Various proposals have also been made to improve this.

For example, French Patent No. 2,485,274 discloses an elastomer material in which a polyethylene oxide/metal ion complex is cross-linked with urethane using shisocyanate, and French Patent No. 2,493,609 discloses a polyester obtained by condensing dimethyl terephthalate with polyglycol or diol. A series of elastomeric polymers are disclosed. Also,
Japanese Patent Publication No. 62-18580 describes a polymer made of polyethylene oxide, which is an ionically conductive polymer containing salts dissolved in an organometallic polymer containing one of aluminum, zinc, and magnesium (ionic conductivity: 52°C).
10-'S/cm), but JP-A-60-262852 describes a polymer made of polyethylene oxide, which contains a metal soluble in an organometallic polymer containing one of cadmium, titanium, and boron. An ionically conductive polymer (ionic conductivity: 10-'S/cm at 65°C) is shown.

[Problems to be Solved by the Invention] However, these solid electrolyte materials have an ionic conductivity of 1O-5S/cm or less at room temperature, and are of little practical use. The easily polymerizable divinyl phosphoric acid monomer having an ethylene chain or a mixture of a vinyl monomer and an alkali metal salt exhibits a relatively high ionic conductivity of 10-'S/cm at room temperature.
Purification of the product is complicated and the yield is not sufficient.

The purpose of the present invention is to have high ionic conductivity (and sufficient ionic conductivity even near or below room temperature, not to react with electrode metal when a battery is constructed, and to be able to be formed into a thin film. The object of the present invention is to provide a solid electrolyte material that has the necessary flexibility when formed into a large-area film and that can be manufactured industrially.

[Means for Solving the Problems 1] The present invention achieves the above object by crosslinking a specific polyglycerin main chain and addition polymerization of polyether to the side chain to form a polymer matrix. It is.

That is, the present invention provides a solid electrolyte mainly consisting of a polymer matrix and an ionic compound, in which the polymer matrix has an average degree of polymerization or an average degree of condensation of 3 or more,
and an ion conductive solid electrolyte material characterized in that it is made of a three-dimensionally crosslinked product obtained by crosslinking an addition polymer having a main chain of polyglycerin and a side chain of polyether having a kinematic viscosity of 1000 cSt or more. be.

[Detailed Description of the Invention] (1) Polymer Matrix Polyglycerin In the polymer solid electrolyte material of the present invention, the polyglycerin that forms the skeleton of the polymer matrix is formed by dehydration condensation of glycerin with an alkali catalyst, condensation of epichlorohydrin with caustic soda, Alternatively, it can be easily obtained by addition polymerization of chrycidol using an addition polymerization catalyst such as caustic soda.

The polyglycerin used in the present invention has an average degree of polymerization or condensation of 3 or more, and a kinematic viscosity of 0'C of 1000 cSt or more, preferably an average degree of polymerization or condensation of 5 or more. , its kinematic viscosity 'l' S
O'C is 5000 cSt or more.

The upper limit of the average degree of polymerization or the average degree of condensation is not restricted from the performance standpoint of the solid electrolyte obtained, but the upper limit of the average degree of polymerization or average degree of condensation of polyglycerin that is usually commercially available is about 10. be.

However, in the polyethylene oxide adduct of glycerin alone, the ionic conductivity at room temperature is 1O-
If the average degree of polymerization or average degree of condensation of the polyglycerin is too low, the ionic conductivity will decrease, so the average degree of polymerization or average degree of condensation of the polyglycerin used is preferably 3 or more, particularly 5 or more. Preferably.

Depending on the polymerization conditions, polyglycerin may also contain some cyclic ether. In that case, if the kinematic viscosity of polyglycerin is too low at 0°C, the ionic conductivity will be low. Kinematic viscosity is 100cS
t or more, preferably 5000 cSt or more.

Polyether The polyether used in the present invention is, for example, a homopolymer or copolymer of alkylene oxide such as ethylene oxide or propylene oxide, and polyethylene glycol having a repeating unit number of 5 to 2000, preferably 10 to 1000. Ether, polypropylene glycol ether, fcIH2-CH2-0-1- group and -(CH2-CH-
01-group random, block, or sea fence copolymer (wherein R is an alkyl group, an alkenyl group, a halogenated alkyl group, or an alkoxy group)
The number of repeating units of ethylene oxide is 5 to 2000
, preferably lO to 1000, and the number of repeating units of propylene oxide is 1 to 1000, preferably 1 to 50.
I can list 0. Among these, particularly preferred are those in which the number of repeating units of ethylene oxide is 5.
-2000, preferably lO -1000 ethylene oxide.

An addition polymer having polyglycerin as a main chain and the above-mentioned polyether as a side chain can be obtained by addition polymerizing alkylene oxide to polyglycerin. That is,
An alkali catalyst is added to polyglycerin under normal alkylene oxide addition conditions (temperature 50-200°C, preferably 100-150°C, reaction pressure 10kg/cm2).
It can be produced by reacting alkylene oxide with (below).

If the number of alkylene oxides added to polyglycerin is less than 5, the crosslinked film will have insufficient flexibility and its ionic conductivity as a solid electrolyte will be low. Also,
If the number of additions is 2000 or more, the viscosity of the addition polymerization reaction solution becomes too high, which is not preferable for industrial production.

The alkylene oxide used here is preferably ethylene oxide, but a second cyclic ether can be added in order to make it amorphous at a lower temperature. The second cyclic ether is represented by the formula %, where R is an alkyl group, alkenyl group, halogenated alkyl group, or alkoxy group, and the number of carbon atoms in R is 1.
~3 is preferred. These cyclic ethers include propylene oxide, epichlorohydrin, methoxyglycidyl ether, and the like. The amount of the second cyclic ether added is preferably 1 to 1,000, preferably 1 to 500. If the number of additions exceeds 1000, the ionic conductivity at high temperatures will decrease, which is not preferable.

(2) Ionic compound component The ionic compound used for the ionic compound component of the polymer solid electrolyte material is not particularly limited, but includes, for example, lithium perchlorate, lithium trifluorosulfonate, lithium tetrakis(trimethylsiloxy)alanate,
Lithium compounds such as lithium bistrifluoromethylacetyl can be used.

The amount of ionic compound present in the polymeric solid electrolyte material is preferably an oxygen/ionic metal, eg, oxygen/lithium ratio of 5:1 to 100:l. If the ratio of oxygen/ionic metal, for example oxygen/lithium, is less than 100:l or greater than 5°1, the ionic conductivity will be low.

(3) Crosslinking The solid polymer electrolyte material used in the present invention is crosslinked, and the crosslinking may be carried out by either chemical or physicochemical methods. Examples include urethane crosslinking using isocyanates, and ionic crosslinking using divalent or higher valent metals such as aluminum, silicon, boron, cadmium, titanium, zinc, magnesium, and tin.

(4) Other components If active hydrogen exists in the polymer solid electrolyte material of the present invention, it will react with lithium used in battery electrodes and inhibit battery performance, so the terminal OH of the polymer matrix should be inactivated. For this purpose, it is preferable to use compounds which are inactivated by chemical or physicochemical methods.

Methods for inactivating such active hydrogen include urethane crosslinking with diisocyanate, which also serves as the above crosslinking;
Alternatively, in addition to the ionic crosslinking method using divalent or higher valent metals such as aluminum, silicon, boron, cadmium, titanium, zinc, magnesylime, tin, etc., a method of blending -valent alkali metals such as lithium, sodium, etc. is available.

The solid polymer electrolyte material used in the present invention may be mixed with an appropriate amount of an organic solvent containing no active hydrogen and having a high dielectric constant, such as γ-butyrolactone, propylene carbonate, polyethylene glycol dimethyl ether, and the like. These solvents act as plasticizers for solid electrolyte materials.
It has the effect of increasing the flexibility of the membrane.

A film obtained by adding an ionic compound such as lithium perchlorate to a polymer compound obtained by addition polymerizing ethylene oxide or ethylene oxide and another cyclic ether such as propylene oxide to the polyglycerin employed by the present inventors, and crosslinking with a crosslinking agent such as tolylene diisocyanate. is an ionically conductive polymer material that is transparent, highly flexible, can be made into a thin film, and can easily be made into a large area.

Example Next, the present invention will be explained by specific examples.

Example 1 Production of high matrix A 480 g of polyglycerin (average degree of polymerization n = 10) with kinematic viscosity (υso°C) 17000 cSt was charged into a 52 autoclave, 20 g of a 20% KOH aqueous solution was added, and after stirring and mixing, dehydration was carried out under reduced pressure. did. When water no longer distilled out at room temperature, the temperature was gradually raised to 100°C to completely dehydrate. Next, the temperature is 120℃ or less and the pressure is 4kg.
3343 g of ethylene oxide was introduced from the cylinder over 2 hours while adjusting the flow rate so that the flow rate was less than /cm2. After the introduction was completed, the reaction was completed by aging at 120°C for 1 hour. Next, the main component 1914 was removed from the autoclave.
g was extracted to obtain Compound A (10 moles of ethylene oxide added to 1 OH group of polyglycerin).

Production of ion conductive solid electrolyte After dissolving 0 g of the above compound Al and 0.45 g of lithium perchlorate in 20 g of acetonitrile, 1.73 g of tolylene diisocyanate was added, this was poured onto a polypropylene film, and the solvent was distilled off under reduced pressure. 48 at 80°C
After reacting for a period of time, a transparent and flexible film was obtained. Next, gold electrodes were attached to both sides of the film by sputtering, and then the conductivity was determined by Cole-Cole plot measurement. The measurement results of electrical conductivity are shown in Table 1.

Example 2 High Matrix 1 Into the remaining autoclave from which Compound A was extracted in Example 1, 1672 g of ethylene oxide was introduced from a cylinder over a further 2 hours under the same conditions. After installation, 1
The reaction was completed by aging at 20° C. for 1 hour. After aging, the product was extracted from the autoclave to obtain Compound B (20 moles of ethylene oxide added to 1 OH group of polyglycerin).

After dissolving 810 g of an ion conductive solid electrolyte compound and 0.45 g of lithium perchlorate in 20 g of acetonitrile, 0.93 g of tolylene diisocyanate was added, this was poured onto a polypropylene film, the solvent was distilled off under reduced pressure, and the temperature was heated to 80°C. After reacting for 48 hours, a transparent and flexible film was obtained.

The measurement results of electrical conductivity are shown in Table 1.

Example 3 High Matrix C Compound C was obtained by performing the same synthesis as in Example 1 except that 100 moles of ethylene oxide was added to 1 polyglycerin OH group in the production of the polymer matrix of Example 1.

Ionic conductivity In the production of the polymer matrix of electrolyte Example 1, a transparent and flexible membrane was obtained in the same manner as in Example 1, except that the compound ClOg and 0 and 20 g of tolylene diisocyanate were used. The measurement results of electrical conductivity are shown in Table 1.

Example 4 High Matrix D To the polyglycerin used in Example 1, 97 mol of ethylene oxide and 3 mol of propylene oxide were randomly added per 1 group of polyglycerin 011 under the same synthesis conditions as in Example 1. , the compound was obtained.

Ion conductive monopolylyte Example 3 In producing the ion conductive solid electrolyte material of Example 3, a transparent and flexible membrane was obtained in the same manner as in Example 3, except that the compound DlOg was used. The measurement results of electrical conductivity are shown in Table 1.

Example 5 High Matrix E Compound A produced in the production of the polymer matrix in Example 1 was used as a starting material, and 1 mol of propylene oxide was added to 1 011 group under the same production conditions as in Example 1. After that, 9 moles of ethylene oxide were added successively. After that, the addition of propylene oxide and ethylene oxide was continuously repeated nine times to obtain OHH of compound A.
A sea fence compound E was obtained in which A(PO, EO9) was used for I3.

Ion conductive/electrolyte A transparent and flexible membrane was obtained in the same manner as in the production of the ion conductive solid electrolyte material in Example 3, except that 10 g of the above compound E was used. The measurement results of electrical conductivity are shown in Table 1.

Example 6 Compound E1Og obtained in the production of the polymer matrix of Example 5 and 0.45 g of lithium perchlorate were dissolved in acetonitrile, 0.45 g of a 15% toluene solution of triethylaluminum was added, and the mixture was poured onto a polypropylene film. After distilling off the solvent under reduced pressure, the mixture was reacted at 80°C for 48 hours to obtain a transparent and flexible film. The measurement results of electrical conductivity are shown in Table 1.

Example 7 High Matrix F A (MGE,
E09) 9 Seafence Compound F was obtained.

Ion conductive electrolyte A transparent and flexible membrane was obtained in the same manner as in the production of the ion conductive solid electrolyte in Example 3, except that the above compound FlOg was used. The measurement results of electrical conductivity are shown in Table 1.

Example 8 Using polyglycerin (average degree of polymerization n.3) with a high matrix G kinematic viscosity (νsoy) of 2000 cSt as a starting material, 20 mol of ethylene oxide was added to 1 OH group in the same manner as in Example 1 to form a compound. I got a G.

Ion conductive electrolyte: 10 g of the above compound G and 0.9 tolylene diisocyanate
A transparent and flexible film was obtained in the same manner as in Example 1, except that 4 g was used. The measurement results of electrical conductivity are shown in Table 1.

Example 9 Using polyglycerin (average degree of polymerization n.15) of polymer matrix H kinematic viscosity (V 5o C) 25000 cSt as a starting material, 20 mol of ethylene oxide was added to OHHI3 in the same manner as in Example 1, and compound H I got it.

Ionic conductive solid electrolyte The above compound HlOg, tolylene diisocyanate 0.9
A transparent and flexible film was obtained in the same manner as in Example 1, except that 2 g was used. The measurement results of electrical conductivity are shown in Table 1.

Comparative Example 1 High Matrix■ Kinematic viscosity (v 5oc) 1516 g of polyglycerin (average degree of polymerization n=10) of 117000 cSt was charged into a No. 51 Oofrepe, and 5 g of a 20% KOH aqueous solution was added.

After stirring and mixing, the mixture was dehydrated under reduced pressure. When water no longer distilled out at room temperature, the temperature was gradually raised to 100°C to completely dehydrate. Next, the temperature is 120℃ or less and the pressure is 4K.
3168 g of ethylene oxide was introduced from the cylinder over 2 hours while adjusting the flow rate so that the flow rate was below g/cm2. After the introduction, the reaction was completed by aging at 120°C for 1 hour, and 4684g of compound (polyglycerin O
3 moles of ethylene oxide were added to 1 H group).

10 g of ion conductive/electrical compound I and 0.33 g of lithium perchlorate were dissolved in 20 g of acetonitrile, 4.46 g of tolylene diisocyanate was added, this was poured onto a polypropylene film, the solvent was distilled off under reduced pressure, and the mixture was heated at 80°C. A transparent film was obtained by reacting for 48 hours. This membrane had poor flexibility.

Gold electrodes were attached to both sides of the film by sputtering, and the conductivity measurement results from Cole-Cole plot were plotted together with the results of Example 1.
Shown in the table.

Comparative Example 2 High Matrix J Compound J was obtained by adding 10 moles of ethylene oxide to OHHI3 in the same manner as in the production of the polymer matrix in Example 1 using monoglycerin as a starting material.

A transparent and flexible membrane was obtained in the same manner as in the production of the ion conductive solid electrolyte material in Example 1, except that 10 g of the ion conductive heavy electrolyte compound J was used.

The measurement results of electrical conductivity are shown in Table 1.

Comparative Example 3 High In the same manner as in Example 1, 10 moles of ethylene oxide and 1190 moles of propylene oxide were randomly added to the polyglycerin used in Example 1 for the matrix, and the compound I got K.

Ion conductive electrolytic compound K 50g, tolylene diisocyanate 0.07
A transparent and flexible film was obtained in the same manner as in Example 1, except that 1.85 g of lithium perchlorate and 1.85 g of lithium perchlorate were used.

The measurement results of electrical conductivity are shown in Table 1.

[Effects of the Invention] The ion conductive polymer solid electrolyte material of the present invention is a three-dimensional crosslinked product in which polyglycerin is the main chain, polyether is the side chain, and crosslinking is performed by the terminal OH of the polyether. Because it is used in this way, the decrease in conductivity due to crystallization is small.

Shows excellent conductivity even near room temperature. Furthermore, since it is crosslinked at the end of a long side chain, it is flexible and can be made into a thin film.

Table 1

Claims (6)

[Claims] (1) In a solid electrolyte mainly composed of a polymer matrix and an ionic compound, the polymer matrix mainly contains polyglycerin whose average degree of polymerization or average degree of condensation is 3 or more and whose kinematic viscosity ν_5_0_°C is 1000 cSt or more. An ion conductive solid electrolyte material comprising a three-dimensionally crosslinked product obtained by crosslinking an addition polymer having polyether as a chain and a side chain. (2) The ionically conductive solid electrolyte material according to claim 1, wherein the polyglycerin is a condensate of glycerin or epichlorohydrin, or a polymer of glycidol. (3) Polyether is a homopolymer of ethylene oxide or ethylene oxide and is represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (where R is an alkyl group, alkenyl group, halogenated alkyl group, or alkoxy group) The ionically conductive solid electrolyte material according to claim 1 or 2, which is a random or sequence copolymer with alkylene oxides and has 5 to 2,000 repeating units of ethylene oxide. (4) The ion conductive solid electrolyte material according to claim 3, wherein the alkylene oxide is propylene oxide, and the number of repeating units thereof is 1 to 1000. (5) Claims 1 to 4, wherein the crosslinking agent is an isocyanate.
The ionically conductive solid electrolyte material described in . (6) The ion according to any one of claims 1 to 4, wherein the crosslinking agent is an organometallic compound containing at least one element selected from the group consisting of aluminum, silicon, boron, titanium, cadmium, magnesium, and tin. Conductive solid electrolyte material.