JP3533289B2 - Lithium ion conductive solid electrolyte molded body - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lithium ion conductive solid electrolyte in which a mobile ionic species is lithium ion.

[0002]

2. Description of the Related Art In recent years, with the development of portable devices such as personal computers and mobile phones, the demand for batteries as a power source thereof has become very large. In particular,
Since lithium has a small atomic weight and a large ionization energy, lithium batteries have been extensively studied as batteries that can obtain high energy density, and are now widely used as power sources for portable devices. Has arrived. On the other hand, along with the generalization of lithium batteries, the increase in the internal energy due to the increase in the content of active materials and the increase in the content of the organic solvent, which is a combustible substance used in the electrolyte, have caused concern about battery safety. Has been getting closer in recent years.

As a method for ensuring the safety of the lithium battery, it is extremely effective to use a solid electrolyte, which is a nonflammable substance, in place of the organic solvent electrolyte, and an all solid lithium battery having high safety. Development is desired. Known lithium ion conductive solid electrolytes for such batteries are lithium halide, lithium nitride, lithium oxyacid salt, and derivatives thereof. In _{addition, Li 2 S-SiS 2,} Li 2 S
_{-P 2 S 5, Li 2 S} -B lithium ion conductive sulfide such as ₂ S ₃ amorphous solid electrolytes and lithium halide such as LiI in these glasses, doped with lithium salt such as Li ₃ PO ₄ The lithium ion conductive solid electrolyte is 10
It is known to show a high ionic conductivity of ^-4 to 10 ^-3 S / cm.

These solid electrolytes are ceramics or glass, and when applied to batteries, they are generally used in the form of pellets obtained by pressure-molding crushed solid electrolyte powder. However, since the obtained pellets are hard and brittle, they have a problem that they are poor in workability and it is difficult to make them thin. In contrast to these inorganic solid electrolytes, a solid electrolyte composed of an organic substance is obtained by evaporating a solvent from a solution of a lithium salt and an organic polymer compound, and thus it is easier to form a thin film than an inorganic solid electrolyte. Also, the obtained solid electrolyte thin film has flexibility and is highly workable.

[0005]

However, the solid electrolyte made of an organic material has an ionic conductivity of 10 at room temperature.
^{It was} as low as ^-4 S / cm or less, which was insufficient as a practical electrolyte for lithium batteries. In order to solve this problem, a polymer solid electrolyte having an increased ionic conductivity by adding a plasticizer has also been proposed. However, since the plasticizer is inherently flammable, the addition of the plasticizer causes problems such as a decrease in the lithium ion transport number and a decrease in the reactivity with the lithium negative electrode. It has been difficult to say that these organic solid electrolytes have sufficient performance as an electrolyte for lithium batteries regardless of the addition of a plasticizer.

Solving the problems of this polymer solid electrolyte,
Furthermore, as a solid electrolyte having flexibility or rubber elasticity, it has recently been named a "polymer in salt" type composed of an inorganic salt and a polymer having extremely high concentration of lithium ion conductivity as compared with the above-mentioned polymer solid electrolyte. A new solid electrolyte proposed by CA Angell et al. (C.
A. Angell, C. Liu, and E. Sanchez, Nature, vol.63
2, (1993) 137). However, most of the conductivity of the "polymer in salt" type solid electrolyte proposed by Angell et al. Is as low as 10 ^-5 S / cm or less, which is a sufficient ionic conductivity as an electrolyte for lithium batteries. It could not be said that it has. Further, when a room temperature molten salt such as AlCl ₃ —LiBr—LiClO ₄ is used as the inorganic salt, it exhibits high ionic conductivity, but electrochemical electrochemical reduction of aluminum is likely to occur, which is suitable as an electrolyte for lithium batteries. I couldn't say that.

An object of the present invention is to solve the above problems and to provide a lithium ion conductive solid electrolyte molded body having high ion conductivity, flexibility and excellent workability. .

[0008]

The present invention is directed to an addition reaction of a sulfuric acid anhydride or a sulfuric anhydride-electron donating compound complex with a polymer having a carbon-carbon double bond in the molecule (hereinafter referred to as a sulfonation reaction). A novel lithium ion conductive solid electrolyte molded body is obtained from the polymer (hereinafter, referred to as a specific polymer) thus obtained and the lithium ion conductive inorganic solid electrolyte. As the above-mentioned polymer, the ratio of the monomer unit to which sulfuric acid anhydride or a sulfuric anhydride-electron donating compound complex is added, that is, the ratio of the sulfonated monomer unit, to all the monomer units constituting the polymer It is preferable to use one having a sulfonation rate of 5 mol% or more and 50 mol% or less. As the lithium ion conductive inorganic solid electrolyte, an amorphous one mainly containing sulfide is used. Further, the amorphous lithium ion conductive inorganic solid electrolyte is preferably one synthesized from a substance mainly containing lithium sulfide or silicon sulfide. Moreover, further electronically insulating structure Zotai <br/> viewed free of a mesh or a nonwoven fabric, the polymer and the lithium ion conductive inorganic
Solid electrolyte fills the opening of the electronically insulating structure.
And a lithium ion conductive solid electrolyte molded body.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION When a polymer compound is mixed in order to impart flexibility to an inorganic lithium ion conductive solid electrolyte, the surface of the lithium ion conductive inorganic solid electrolyte particles becomes an insulating polymer compound. It will be covered with. As a result, the ionic conduction between the solid electrolyte particles is hindered, and the ionic conductivity of the obtained composite of the lithium ion conductive inorganic solid electrolyte and the polymer compound is low. The present inventors have used, as the polymer compound, a polymer obtained by adding sulfuric anhydride or a sulfuric anhydride-electron-donating compound complex to a carbon-carbon double bond in the molecule, to obtain a lithium ion conductive inorganic solid electrolyte. It has been found that it is possible to impart flexibility to the lithium ion conductive inorganic solid electrolyte and achieve high processability without hindering the movement of lithium ions between particles. Below, as a polymer compound for improving the processability of the lithium ion conductive inorganic solid electrolyte,
The mechanism by which the polymer does not hinder the ionic conduction between the lithium ion conductive inorganic solid electrolyte particles when the polymer obtained by sulfonation of the carbon-carbon double bond is used will be described.

When the double bond of the polymer having a side chain having a carbon-carbon double bond represented by Chemical formula 1 is reacted with, for example, sulfuric anhydride, a sulfuric anhydride-electron donating compound complex, etc. The side chains of the united body are sulfonated to form side chains having a cyclic structure as shown in Chemical formula 2, for example.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

When such a polymer is reacted with an inorganic lithium ion conductive solid electrolyte, the ring structure is opened. As a result, between the lithium ion in the lithium ion conductive inorganic solid electrolyte and the polymer compound, for example,
The electrical interaction indicated by the broken line in FIG.

[0014]

[Chemical 3]

That is, the lithium ions are in a state of being electrically loosely bound to the side chains as described above, and on the other hand, such side chains perform segmental motion due to thermal vibration. As a result, when the lithium ion conductive inorganic solid electrolytes having the above-described structure formed on the surface are brought into contact with each other, lithium ions move between the lithium ion conductive inorganic solid electrolyte particles due to the segmental motion of the side chain of the polymer. It can move and impart flexibility without disturbing ionic conduction between particles.

However, when such a sulfonated side chain is present in a large amount in the polymer, the rubber elasticity of the polymer is lost and the processability of the obtained lithium ion conductive solid electrolyte molded article is deteriorated. Therefore, as a polymer obtained by sulfonation of a carbon-carbon double bond, a high ionic conductivity, and a lithium ion conductive solid electrolyte molded article having a high processability is obtained, the sulfonation rate is Those of 5 mol% or more and 50 mol% or less are particularly preferably used. Further, in order to efficiently form an electrical interaction between the lithium ion and the polymer, it is desirable to heat the mixture after mixing the lithium ion conductive inorganic solid electrolyte and the polymer. The heat treatment temperature is preferably in the temperature range of 120 ° C to 210 ° C at which the solid electrolyte molded article exhibits high ionic conductivity and the polymer is not decomposed.

The specific polymer used in the present invention is obtained by sulfonation of a polymer having a carbon-carbon double bond in the molecule with, for example, sulfuric anhydride, sulfuric anhydride-electron donating compound complex, or the like. The polymer having a carbon-carbon double bond in the molecule is, for example, selected from the group consisting of monomers having two or more carbon-carbon double bonds in the molecule (hereinafter, also referred to as a specific monomer). (Co) polymers of at least one compound mentioned above. Specific examples of the specific monomer include 1,3-butadiene and 1,2-butadiene.
Butadiene, 1,2-pentadiene, 1,3-pentadiene, 2,3-pentadiene, isoprene, 1,2-hexadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,3- Hexadiene,
2,4-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,2-
Heptadiene, 1,3-heptadiene, 1,4-heptadiene, 1,5-heptadiene, 1,6-heptadiene, 2,3-heptadiene, 2,5-heptadiene,
3,4-heptadiene, 3,5-heptadiene, cyclobutadiene, cyclohexadiene, cyclopentadiene, dicyclopentadiene, cyclooctatriene, vinyl norbornene, ethylidene norbornene, propenyl norbornene, isopropenyl norbornene and the like, among them, 1, 3-Butadiene, isoprene, dicyclopentadiene and ethylidene norbornene are preferred. These specific monomers can be used alone or in combination of two or more kinds.

Further, a copolymer obtained by using a specific monomer in combination with another monomer can also be used. Specific examples of other monomers include, for example, styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl methyl ethyl ketone, vinyl methyl ether, vinyl acetate, Vinyl group-containing compounds such as vinyl formate and allyl alcohol; (meth) acrylic acid, (meth)
Methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide, (meth) (Meth) acryloyl group-containing compounds such as glycidyl acrylate; mono- or dicarboxylic acid anhydrides such as crotonic anhydride, maleic anhydride, fumaric anhydride, and itaconic anhydride. The ratio of these other monomers to be used is not particularly limited, but is usually less than 98% by weight, preferably less than 95% by weight. When 98% by weight or more of another monomer is used, the number of carbon-carbon double bonds to be sulfonated decreases, so that a specific polymer having sufficient lithium ion conductivity may not be obtained.

As the polymerization initiator used in the polymerization reaction of the above (co) polymer, there are radical polymerization initiators such as potassium persulfate, sodium persulfate, hydrogen persulfate, azobisisobutyronitrile and benzoyl peroxide. Anionic polymerization initiators such as alkali metals, n-butyllithium, sodium naphthalene; sulfuric acid, phosphoric acid, perchloric acid,
Cationic polymerization initiators such as boron trifluoride, aluminum chloride, titanium tetrachloride, tin tetrachloride; Ziegler catalysts such as triethylaluminum-titanium tetrachloride. A solvent may be used in the polymerization reaction of the (co) polymer. Examples of usable solvents include n-pentane, n-hexane, cyclohexane, n
-Hydrocarbon solvents such as heptane, octane, benzene, toluene, xylene, ethylbenzene; ethers,
Ether-based solvents such as dioxane and tetrahydrofuran, halogenated solvents such as carbon tetrachloride and chloroform;
Examples include water.

The reaction of the above (co) polymer is usually -100.
The reaction temperature is determined by the types of the monomer, the polymerization initiator and the solvent. Above (Co)
The polymer has a polystyrene-reduced weight average molecular weight of usually 500 to 5,000,000, and preferably 1,000 to 1,000,000. When the weight average molecular weight is less than 500, the rubber elasticity of the obtained specific polymer may be insufficient, while when it is 5,000,000 or more, the solubility in an organic solvent may be poor. Further, there is no particular limitation on the polymerization mode of the (co) polymer,
Various structures such as random type, block type, graft type and star type can be adopted. Preferred (co) polymers include polyisoprene, polybutadiene, styrene-isoprene copolymers, styrene-butadiene copolymers, ethylene-propylene-diene copolymers and their partially hydrogenated products.

The specific polymer used in the present invention is sulfonated by using the carbon-carbon double bond in the (co) polymer as a sulfonating agent, for example, sulfuric anhydride, sulfuric anhydride-electron donating compound complex or the like. Obtained by reacting.
Here, as the electron-donating compound, ethers such as N, N-dimethylformamide, dioxane, dibutyl ether, tetrahydrofuran and dimethyl ether; amines such as pyridine, piperazine, trimethylamine, triethylamine and tributylamine, dimethyl sulfide and diethyl sulfide. And nitriles such as acetonitrile, ethyl nitrile, and propyl nitrile; phosphorus compounds such as triethyl phosphite and tributyl phosphite; and dioxane is preferable. The amount of sulfonating agent such as sulfuric anhydride, sulfuric anhydride-electron donating compound complex, etc. is usually 1 to 80 mol% in terms of sulfuric anhydride, based on all monomer units constituting the (co) polymer. It is preferably 5 to 50 mol%. If it is less than 1 mol%, the lithium ion conductivity of the obtained specific polymer may not be sufficient, while if it exceeds 80 mol%, the rubber elasticity of the obtained specific polymer may be lost and the lithium ion conductive solid electrolyte may be lost. The processability when formed into a molded product may decrease. In particular, as the specific polymer capable of obtaining a lithium ion conductive solid electrolyte molded article having high lithium ion conductivity and good processability, those having a sulfonation rate of 5 mol% or more and 50 mol% or less are preferable. Used.

In the above sulfonation reaction, a solvent inert to the sulfonating agent may be used. Examples of usable solvents include halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, tetrachloroethane, and tetrachloroethylene; nitromethane,
Nitro compounds such as nitrobenzene; liquid sulfur dioxide,
Aliphatic hydrocarbons such as propane, butane, pentane, hexane and cyclohexane; and ethers such as dioxane. These solvents may be used alone or in combination of two or more. The reaction temperature in the sulfonation reaction is usually -50 to 100 ° C, preferably -30 to 50 ° C. If it is lower than -50 ° C, the sulfonation reaction may be delayed, while if it is higher than 100 ° C, a side reaction may occur and the resulting specific polymer may be blackened or insolubilized.

The specific polymer thus obtained is
The structure consisting of SO ₂ —O— has a cyclic structure bonded to a carbon atom of the main chain or a side chain, and has a structure such as chemical formula 4 or chemical formula 2 above.

[0024]

[Chemical 4]

As the lithium ion conductive inorganic solid electrolyte, those having high ionic conductivity and a wide potential window are preferable, and those having both of these characteristics are particularly amorphous ones mainly composed of sulfide. preferable. Further, as the lithium ion conductive amorphous inorganic solid electrolyte mainly composed of sulfide, when lithium sulfide or silicon sulfide is used as the starting material, the vapor pressure of the starting material becomes low, and the starting material for solid electrolyte synthesis is It is possible to suppress transpiration. Therefore, since the method for synthesizing the solid electrolyte can be simplified, as the lithium ion conductive amorphous inorganic compound, those synthesized from a substance mainly containing lithium sulfide or silicon sulfide are particularly preferably used. . Moreover, the mechanical strength of the lithium ion conductive solid electrolyte molded body can be further increased by adding an electronically insulating structure.

[0026]

EXAMPLES Examples of the present invention will be described in detail below. The synthesis of the lithium ion conductive inorganic solid electrolyte described below and the measurement of the ionic conductivity thereof were all performed in a dry argon atmosphere. First, a synthesis example of the specific polymer will be described.

[Synthesis Example 1] 500 g of sufficiently dehydrated dioxane was placed in a 1 liter separable flask, the temperature in the flask was kept in the range of 10 to 30 ° C., and 32.5 g of anhydrous sulfuric acid was added dropwise while stirring. To obtain a sulfuric anhydride-dioxane complex. In a 3 liter separable flask,
80 g of an isoprene-styrene copolymer having a weight average molecular weight of 200,000 (isoprene / styrene = 70/30 (molar ratio)) was added and sufficiently dehydrated dioxane 800.
g was added to dissolve the copolymer, the above sulfuric anhydride-dioxane complex was added, and the specific polymer (S-1) was obtained by sulfonation reaction at 25 ° C. for 2 hours. The amount of sulfonated monomer units was determined by elemental analysis, and the sulfonation rate was calculated to be 40%.

[Synthesis Examples 2 to 18] As shown in Table 1, specific polymers were obtained and sulfonated in the same manner as in Synthesis Example 1 except that the type of copolymer and the amount of sulfuric anhydride used were changed. The rate was calculated. The results are also shown in Table 1.

[0029]

[Table 1]

In Table 1, the abbreviations represent the following, respectively. IP: isoprene, ST: styrene, BD: butadiene, ET: ethylene, PP: propylene, DCP: dicyclopentadiene.

Correspondence between the following examples and the numbers of the specific polymers used is as shown in Table 2.

[0032]

[Table 2]

Example 1 A sulfide glass represented by 0.6Li ₂ S-0.4SiS ₂ as a lithium ion conductive inorganic solid electrolyte and a sulfonated isoprene-styrene random copolymer as a specific polymer. Using each of (S-1), a lithium ion conductive solid electrolyte molded body was obtained. The details are shown below. First, as a lithium ion conductive inorganic solid electrolyte, 0.6 Li was prepared by the following method.
A lithium ion conductive amorphous solid electrolyte represented by ₂ S-0.4SiS ₂ was synthesized. Lithium sulfide (Li ₂ S)
And silicon sulfide (SiS ₂ ) were mixed at a molar ratio of 3: 2, and the mixture was put into a glassy carbon crucible. The crucible was placed in a vertical furnace and heated in an argon stream to 95
The mixture was heated to 0 ° C. to bring the mixture into a molten state. After heating for 2 hours, drop the crucible into liquid nitrogen and quench it to 0.6 L.
A lithium ion conductive amorphous solid electrolyte represented by i ₂ S-0.4SiS ₂ was obtained.

A lithium ion conductive solid electrolyte molded body was obtained by the following method from the lithium ion conductive amorphous solid electrolyte thus obtained and the specific polymer (S-1). First, the solid electrolyte obtained above was pulverized to 350 mesh or less. A dioxane solution of (S-1) was added to this solid electrolyte powder and sufficiently kneaded to form a slurry. The mixing ratio during kneading was such that the weight ratio of the solid content of the isoprene-styrene copolymer to the solid electrolyte powder was 5:95. The slurry thus obtained was applied onto a fluororesin plate by the doctor blade method, and dioxane was evaporated under a reduced pressure of 180 ° C. to dry. After drying for 3 hours, it was peeled from the fluororesin plate to obtain a lithium ion conductive solid electrolyte molded body. The ionic conductivity of this lithium ion conductive solid electrolyte molded body was measured by the AC impedance method described below. First, the sheet of the lithium ion conductive solid electrolyte molded body obtained above was cut into a disk shape of 10 mmφ. A 10 mmφ Pt plate was pressed onto both sides of this disk to serve as electrodes for impedance measurement, and an ion conductivity measurement cell was constructed. The AC impedance was measured by applying an AC voltage of 10 mV with a vector impedance analyzer. As a result, the obtained lithium ion conductive solid electrolyte molded body had an ionic conductivity of 2.3 × 1.
It was 0 ⁻⁴ S / cm. In addition, as a comparative example, when a solid electrolyte powder was pressure-molded without adding a specific polymer and its ionic conductivity was measured in the same manner, the ionic conductivity was 4.
It was 5 × 10 ⁻⁴ S / cm.

Next, as an evaluation of the processability of this lithium ion conductive solid electrolyte molded body, a bending test was conducted to examine its flexibility. In the bending test, this lithium ion conductive solid electrolyte molded body was wrapped around a 50 mmφ stainless steel rod and the state of the molded body was visually observed.
As a result, it was found that the lithium ion conductive solid electrolyte molded body of the present example had a high flexibility without any abnormality in appearance even in the bending test. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 2 A lithium ion conductive material was prepared in the same manner as in Example 1 except that (S-2) was used as the specific polymer instead of (S-1) used in Example 1. A solid electrolyte molded body was obtained. The ionic conductivity of this lithium ion conductive solid electrolyte molded body was measured in the same manner as in Example 1. The ionic conductivity was 3.2 × 10 ⁻⁴ S / cm.
Met. In addition, the bending test conducted in the same manner as in Example 1 revealed that no abnormalities were found in the external appearance and that it had high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 3 A lithium ion conductive material was prepared in the same manner as in Example 1 except that (S-3) was used instead of (S-1) used in Example 1 as the specific polymer. A solid electrolyte molded body was obtained. The ionic conductivity of this lithium ion conductive solid electrolyte molded body was measured in the same manner as in Example 1. The ionic conductivity was 2.8 × 10 ⁻⁴ S / cm.
Met. In addition, in the bending test conducted in the same manner as in Example 1, no abnormalities were observed in the external appearance, and it was found that it has high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 4 A lithium ion conductive material was prepared in the same manner as in Example 1 except that (S-4) was used as the specific polymer instead of (S-1) used in Example 1. A solid electrolyte molded body was obtained. The ionic conductivity of this lithium ion conductive solid electrolyte molded body was measured in the same manner as in Example 1. The ionic conductivity was 2.6 × 10 ⁻⁴ S / cm.
Met. In addition, in the bending test conducted in the same manner as in Example 1, no abnormalities were observed in the external appearance, and it was found that it has high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 5 0.01 Li ₃ PO ₄ -0.63 Li ₂ S as a lithium ion conductive inorganic solid electrolyte
A lithium ion conductive amorphous solid electrolyte represented by -0.36SiS ₂ and (S-2) as a specific polymer were used in the same manner as in Example 2 to form a lithium ion conductive solid electrolyte molded body. did. The details are shown below.
First, as the lithium ion conductive inorganic solid electrolyte, the following method 0.01Li ₃ PO ₄ -0.63Li ₂ S-
A lithium ion conductive amorphous solid electrolyte represented by 0.36SiS ₂ was synthesized. First, a glass base material for synthesizing an amorphous solid electrolyte was synthesized. Lithium sulfide (Li ₂ S) and silicon sulfide (SiS ₂ ) in molar ratio of 0.6
4: 0.36, and the mixture was put into a glassy carbon crucible and melted at 950 ° C. in a horizontal furnace. afterwards,
The melt was quenched with twin rollers and 0.64 Li ₂ S-0.36
An amorphous solid electrolyte represented by SiS ₂ was obtained. This amorphous solid electrolyte is used as a glass base material, and 0.01 Li ₃
Lithium phosphate was mixed to have a composition of PO ₄ -0.63Li ₂ S-0.36SiS ₂ . The mixture was heated and quenched in the same manner as described above, 0.01Li ₃ PO ₄ -
A lithium ion conductive amorphous solid electrolyte represented by 0.63Li ₂ S-0.36SiS ₂ was obtained. 0.6 Li ₂ S
Lithium was used in the same manner as in Example 1 except that this solid electrolyte was used instead of the solid electrolyte represented by -0.4SiS ₂ and (S-2) used in Example 2 was used as the specific polymer. An ion conductive solid electrolyte molded body was obtained.

The ionic conductivity of this molded lithium ion conductive solid electrolyte was measured in the same manner as in Example 1 and found to be 4.5 × 10 ^-4 S / cm. Also, as a comparative example, the ionic conductivity of the solid electrolyte powder alone was 7.8 × 10 ⁻⁴ S / cm as measured by the same method as in Example 1. In addition, in the bending test conducted in the same manner as in Example 1, no abnormalities were observed in the external appearance, and it was found that it has high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 6 As a lithium ion conductive inorganic solid electrolyte, 0.05Li ₂ O-0.60Li ₂ S-
A lithium ion conductive amorphous solid electrolyte represented by 0.35SiS ₂ and (S-2) as a specific polymer were used as in Example 2 to form a lithium ion conductive solid electrolyte molded body. . The details are shown below.
_{0.05Li 2 O-0.60Li 2 S-} 0.35SiS 2
The lithium ion conductive amorphous solid electrolyte represented by
Other than using lithium oxide in place of lithium phosphate,
It was synthesized in the same manner as in Example 5. A lithium ion conductive solid electrolyte was obtained in the same manner as in Example 1 except that the lithium ion conductive solid electrolyte thus obtained was used and (S-2) used in Example 2 was used as the specific polymer. A molded body was obtained.

When the ionic conductivity of this lithium ion conductive solid electrolyte molded article was measured by the same method as in Example 1, it was 3.9 × 10 ^-4 S / cm. In addition, as a comparative example, the ionic conductivity of the solid electrolyte powder alone was 6.6 × 10 ⁻⁴ S / cm when measured by the same method as in Example 1. In addition, in the bending test conducted in the same manner as in Example 1, no abnormalities were observed in the external appearance, and it was found that it has high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 7 As a lithium ion conductive inorganic solid electrolyte, 0.3LiI-0.35Li ₂ S-0.
A lithium ion conductive amorphous solid electrolyte represented by 35SiS ₂ and (S-1) as a specific polymer were used in the same manner as in Example 1 to form a lithium ion conductive solid electrolyte molded body. The details are shown below. First, as the lithium ion conductive inorganic solid electrolyte, 0.3LiI-0.35Li ₂ S-0.35S in the following manner
A lithium ion conductive amorphous solid electrolyte represented by iS ₂ was synthesized. First, 0.5Li ₂ S-0.5Si was prepared in the same manner as in Example 1 except that the mixing ratio of the starting materials was changed.
An amorphous solid electrolyte represented by S ₂ was obtained. This amorphous solid electrolyte was used as a glass base material, and 0.3 LiI-0.
Lithium iodide was mixed to have a composition of 35Li ₂ S-0.35SiS ₂ . This mixture was again heated and rapidly cooled in the same manner, and 0.3LiI-0.35Li ₂ S-0.
A lithium ion conductive amorphous solid electrolyte represented by 35SiS ₂ was obtained. A lithium ion conductive solid electrolyte molded body was obtained in the same manner as in Example 1 except that this solid electrolyte was used instead of the solid electrolyte represented by 0.6Li ₂ S-0.4SiS ₂ .

When the ionic conductivity of this lithium ion conductive solid electrolyte molded article was measured by the same method as in Example 1, it was 2.6 × 10 ^-4 S / cm. Also, as a comparative example, the ionic conductivity of the solid electrolyte powder alone was measured by the same method as in Example 1 and found to be 7.2 × 10 ⁻⁴ S / cm. Further, it was found that the bending test conducted in the same manner as in Example 1 showed no abnormalities in appearance and had high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 8 As a lithium ion conductive inorganic solid electrolyte, a lithium ion conductive amorphous solid electrolyte represented by 0.5Li ₂ S-0.5P ₂ S ₅ was used, and as a specific polymer. (S-1) was used in the same manner as in Example 1 to form a lithium ion conductive solid electrolyte molded body. The details are shown below. First, as raw materials for the solid electrolyte, lithium sulfide (Li ₂ S) and phosphorus sulfide (P ₂ S ₅ ) are used.
Were mixed at a molar ratio of 0.5: 0.5. This mixture was sealed in a quartz tube and melted at 900 ° C., then the quartz tube was dropped into water and rapidly cooled to 0.5 Li ₂ S-0.5P ₂ S.
_An amorphous solid electrolyte represented by ₅ was obtained. 0.6 Li ₂ S-
A lithium ion conductive solid electrolyte molded body was obtained in the same manner as in Example 1 except that this solid electrolyte was used instead of the solid electrolyte represented by 0.4SiS ₂ . When the ionic conductivity of this lithium ion conductive solid electrolyte molded article and the solid electrolyte powder of the comparative example were measured by the same method as in Example 1, the decrease in ionic conductivity due to the addition of the specific polymer was 1 / It was within 2 Also,
It was found that no abnormality was found in the appearance even in the bending test conducted in the same manner as in Example 1, and that it had high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 9 A lithium ion conductive amorphous solid electrolyte represented by 0.6Li ₂ S-0.4B ₂ S ₃ was used as a lithium ion conductive inorganic solid electrolyte, and a specific polymer was used as an example. (S-1) was used in the same manner as in Example 1 to form a lithium ion conductive solid electrolyte molded body. The details are shown below. First, as raw materials for the solid electrolyte, lithium sulfide (Li ₂ S) and boron sulfide (B ₂ S) are used.
₃₎ in a molar ratio of 0.6: 0.6Li ₂ in except for using a mixture in a ratio of 0.4 the same manner as in Example 8 S-
An amorphous solid electrolyte represented by 0.4B ₂ S ₃ was obtained. 0.
A lithium ion conductive solid electrolyte molded body was obtained in the same manner as in Example 1 except that this solid electrolyte was used instead of the solid electrolyte represented by 6Li ₂ S-0.4SiS ₂ . When the ionic conductivity of this lithium ion conductive solid electrolyte molded article and the solid electrolyte powder of the comparative example were measured by the same method as in Example 1, the decrease in ionic conductivity due to the addition of the specific polymer was 1 / It was within 2 In addition, in the bending test conducted in the same manner as in Example 1, no abnormalities were observed in the external appearance, and it was found that it has high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

[0047] The Li ₁ as "Example 10" lithium ion conductive inorganic solid _{electrolyte. 3 Al 0. 3 Ti 1} . 7 (PO 4) crystalline lithium ion conductive solid electrolyte represented by _3,
Further, (S-1) was used as the specific polymer in the same manner as in Example 1 to form a lithium ion conductive solid electrolyte molded body. The details are shown below. First, lithium carbonate, aluminum oxide, titanium oxide, and orthophosphoric acid were used as raw materials for the solid electrolyte. After these starting materials mixed and pressure molded into pellets and sintered at 1300 ° C. 24 _{h, Li 1. 3 Al 0.} 3 Ti 1. 7 (PO 4) crystalline represented by ₃ lithium ion A conductive inorganic solid electrolyte was obtained. A lithium ion conductive solid electrolyte molded body was obtained in the same manner as in Example 1 except that this solid electrolyte was used instead of the solid electrolyte represented by 0.6Li ₂ S-0.4SiS ₂ .

When the ionic conductivity of this molded lithium ion conductive solid electrolyte was measured by the same method as in Example 1, a value of 1.1 × 10 ^-4 S / cm was shown. Further, as a comparative example, the ionic conductivity of the inorganic solid electrolyte alone without addition of the specific polymer was measured by the following two methods. First,
Platinum thin films were formed on both surfaces of the fired pellets by a sputter deposition method to form electrodes. A lead wire was adhered to this electrode with silver paste to prepare a cell for measuring ionic conductivity. The ionic conductivity of the solid electrolyte alone, which was measured as a sintered body using this measurement cell, showed a value of 3.2 × 10 ⁻³ S / cm. Next, the ionic conductivity of this solid electrolyte was measured using a powder molded body. A platinum plate was placed using the crushed solid electrolyte powder as an electrode, and pressure-molded into a disk shape of 10 mmφ. As a result of measuring the ionic conductivity of the solid electrolyte using this measuring cell, a value of 8.1 × 10 ⁻⁵ S / cm was shown.

As described above, it was found that the lithium ion conductive solid electrolyte molded body according to the present invention has a higher ion conductivity than the powder molded body, although it does not reach the state of the sintered body. The reason why the ionic conductivity measured using the powder compact was only low was that the solid electrolyte was crystalline and the ionic conduction path in the particles was anisotropic. It seems that there is insufficient connection. On the other hand, it is considered that the sintered body exhibited high ionic conductivity because crystal growth occurred between the particles due to sintering and the ionic conduction paths between the particles were connected. Ion conduction between solid electrolyte particles in a solid electrolyte molded body composited with a specific polymer is considered to be isotropic because segment motion of side chains of the polymer is involved. As a result, the connection of the ionic conduction paths between the particles was better than that of the powder molded body, and it is considered that the ionic conductivity was higher. In addition, in the bending test conducted in the same manner as in Example 1, no abnormalities were observed in the external appearance, and it was found that it has high flexibility. As described above, according to the present invention, it was found that a lithium ion conductive solid electrolyte molded body having high lithium ion conductivity and excellent workability can be obtained.

Example 11 As a lithium ion inorganic solid electrolyte, 0.6Li ₂ S-0.4S was used as in Example 1.
An amorphous solid electrolyte represented by iS ₂ and isoprene-styrene random copolymers (S-5-1) to (S-5-8) which are sulfonated at various ratios as specific polymers are used. A lithium ion conductive solid electrolyte molded body was obtained. The details are shown below. (S-5-1) to (S
-5-8) and the lithium ion conductive inorganic solid electrolyte obtained in Example 1 were obtained in the same manner as in Example 1 to obtain a lithium ion conductive solid electrolyte molded body. The relationship between the sulfonation rate of the specific polymer obtained as a result of the AC impedance measurement and the ionic conductivity of the obtained lithium ion conductive solid electrolyte molded article is shown in FIG. From this result, it is understood that by using the isoprene-styrene random copolymer having a sulfonation rate of 5% or more, a lithium ion conductive solid electrolyte molded body having particularly high ion conductivity can be obtained. Further, isoprene-having a sulfonation rate of more than 50%
Regarding the one using the styrene random copolymer, the obtained lithium ion conductor had poor rubber elasticity, and as a result of the bending test conducted in the same manner as in Example 1, the lithium ion conductive solid electrolyte molded body was cracked. Occurred. As described above, according to the present invention in which the sulfonation rate of the specific polymer is 5% to 50%, a lithium ion conductive solid electrolyte molded body having particularly high lithium ion conductivity and excellent processability can be obtained. I understood it.

Example 12 0.01 Li ₃ PO ₄ -0.6 obtained in Example 5 as a lithium ion inorganic solid electrolyte
Styrene-isoprene-styrene block copolymers (S-6-1) to (S) in which an amorphous solid electrolyte represented by 3Li ₂ S-0.36SiS ₂ is sulfonated as a specific polymer in various ratios. -6-8) was used to obtain a lithium ion conductive solid electrolyte molded body. The details are shown below. From (S-6-1) to (S-6-8) and the lithium ion conductive inorganic solid electrolyte obtained in Example 5, a lithium ion conductive solid electrolyte molded body was obtained in the same manner as in Example 1. . FIG. 2 shows the relationship between the sulfonation ratio of the specific polymer obtained as a result of the AC impedance measurement and the ionic conductivity of the obtained lithium ion conductive solid electrolyte molded body.
Shown in. From these results, it can be seen that by using the styrene-isoprene-styrene block copolymer having a sulfonation rate of 5% or more, a lithium ion conductive solid electrolyte molded body having particularly high ion conductivity can be obtained. Further, regarding the one using a styrene-isoprene-styrene block copolymer having a sulfonation rate of more than 50%, the obtained lithium ion conductive solid electrolyte molded article has poor rubber elasticity, and the same method as in Example 1 was used. As a result of the bending test carried out in 1., the lithium ion conductive solid electrolyte molded body was cracked. As described above, according to the present invention in which the sulfonation rate of the polymer compound is 5% to 50%, a lithium ion conductive solid electrolyte molded body having particularly high lithium ion conductivity and excellent processability can be obtained. I understood it.

Example 13 0.01 Li ₃ PO ₄ -0.6 obtained in Example 5 as a lithium ion inorganic solid electrolyte
3Li ₂ S-0.36SiS ₂ Amorphous solid electrolyte and (S-2) as the specific polymer are heat-treated at various temperatures to obtain a lithium ion conductive solid electrolyte molded body. It was The details are shown below. The drying temperature of the slurry was changed in order to change the heat treatment temperature of the lithium ion conductive solid electrolyte molded body. A slurry containing the solid electrolyte and the specific polymer was obtained in the same manner as in Example 1. The thus-obtained slurry was applied onto a fluororesin plate by the doctor blade method, and dioxane was evaporated under reduced pressure while being heated at various temperatures to be dried. Three
After drying for a period of time, it was peeled from the fluororesin plate to obtain a lithium ion conductive solid electrolyte molded body. The relationship between the heat treatment temperature obtained as a result of the AC impedance measurement and the ionic conductivity of the obtained lithium ion conductive solid electrolyte molded body is shown in FIG. From these results, it can be seen that the lithium ion conductive solid electrolyte molded body that has been heat-treated in the temperature range of 120 ° C. to 210 ° C. exhibits particularly high ion conductivity.
As described above, according to the present invention in which the heat treatment is performed in the temperature range of 120 ° C. to 210 ° C., it is found that a lithium ion conductive solid electrolyte molded body having particularly high lithium ion conductivity and excellent workability can be obtained. It was

Example 14 0.01 Li ₃ PO ₄ -0.6 obtained in Example 5 as a lithium ion inorganic solid electrolyte
3Li ₂ S-0.36SiS ₂ is used as the amorphous solid electrolyte, (S-2) is used as the specific polymer, and polyethylene mesh is used as the electronically insulating structure. A solid electrolyte molded body was obtained. The details are shown below. A slurry containing the solid electrolyte and the specific polymer was obtained in the same manner as in Example 1. Then, the slurry was applied to this slurry by a doctor blade method to obtain an aperture ratio of 7
The opening was filled with 0% polyethylene mesh. Then, dioxane was evaporated and dried under reduced pressure at 180 ° C.,
A lithium ion conductive solid electrolyte molded body was obtained. The ionic conductivity of this molded lithium ion conductive solid electrolyte was measured in the same manner as in Example 1, and the ionic conductivity was 2.7 × 10 ⁻⁴ S / cm. In addition, Example 1
In the bending test conducted in the same manner as above, no abnormality was found in appearance, and no abnormality was found in the bending test using the 5 mmφ stainless steel rod, and the lithium ion conductor according to the present example had higher flexibility. It was found to have sex. As described above, according to the present invention using the lithium ion conductive inorganic solid electrolyte, the specific polymer, and the structure having electronic insulation, the lithium ion conductive material having particularly high processability and high lithium ion conductivity is obtained. It was found that a solid electrolyte molded body was obtained.

Example 15 0.01 Li ₃ P used in Example 14 as a lithium ion conductive inorganic solid electrolyte
The lithium ion conductive amorphous solid electrolyte represented by 0.6Li ₂ S-0.4SiS ₂ obtained in Example 1 in place of O ₄ -0.63Li ₂ S-0.36SiS ₂ was used. Instead of (S-2) used in Example 14 as a molecule, (S-
Example 1 as an electronic insulating structure using 1)
A lithium ion conductive solid electrolyte molded body was constructed in the same manner as in Example 14 except that the glass fiber mesh was used in place of the polyethylene mesh used in 4. When the ionic conductivity of the resulting lithium ion conductive solid electrolyte molded body was measured in the same manner as in Example 1,
Its ionic conductivity was 3.1 × 10 ⁻⁴ S / cm.
In addition, no abnormality was found in the appearance in the bending test performed in the same manner as in Example 1, and no abnormality was observed in the bending test using a 5 mmφ stainless steel rod. It was found that the solid electrolyte molded body had higher flexibility. As described above, according to the present invention using the lithium ion conductive inorganic solid electrolyte, the specific polymer, and the structure having electronic insulation, the lithium ion conductive material having particularly high processability and high lithium ion conductivity is obtained. It was found that a solid electrolyte molded body was obtained.

In the examples of the present invention, carbon-
As the polymer obtained by subjecting the carbon double bond to the sulfonation reaction, only the sulfonated isoprene-styrene random copolymer, the sulfonated styrene-isoprene-styrene block copolymer and the like are explained, but as other polymers Needless to say, the same effect can be obtained by using a sulfonated other polymer such as another thermoplastic elastomer, and the present invention is a sulfonation reaction of a carbon-carbon double bond. As a polymer
It is not limited to the polymers described in these examples. Further, in the examples of the present invention, as the lithium ion conductive inorganic solid electrolyte, 0.6 Li ₂ S-0.4 was used.
_{SiS 2, 0.01Li 3 PO 4 -0.63Li} 2 S-0.
36SiS ₂ , 0.5Li ₂ S-0.5P ₂ S ₅ , 0.6L
i ₂ S-0.4B ₂ S ₃ lithium ion conductive amorphous solid electrolytes such as, or _{Li 1.3 Al 0.3 Ti 1 .7 (} P
Although a crystalline lithium ion conductive solid electrolyte represented by O ₄ ) ₃ has been described, those having different component ratios of these solid electrolytes, such as Li ₂ S—GeS ₂ which are not explained in the examples. Containing sulfide of LiCl-Li _{2
S-SiS 2, LiBr-Li} 2 S-P 2 S 5 , such as those containing other lithium halides, also LiI-Li ₂ S-S
_{iS 2 -P 2 S 5, LiI} -Li 3 PO 4 -Li 2 S-SiS
Pseudo-quaternary system such as ₂ , or Li ₃ N, Li
_1.3 Sc _0.3 Ti _1.7 (PO ₄ ) ₃ , Li _0.2 La _0.6 TiO ₃
Needless to say that the same effect can be obtained by using other crystalline lithium ion conductive inorganic solid electrolytes not described in Examples, etc., the present invention is a lithium ion conductive inorganic solid electrolyte, It is not limited to those described in these examples.

Furthermore, the lithium ion conductive inorganic solid electrolyte described in the examples of the present invention has a high ion conductivity of 10 ^-4 S / cm or more at room temperature in the solid state. In contrast, LiPF ₆ , LiBF _{4 and the} like, which show high lithium ion conductivity when ion-dissociated in a solvent, but show only very low ion conductivity at room temperature in the solid state, are carbon-carbon dioxide. By combining with a polymer obtained by subjecting a heavy bond to a sulfonation reaction, an electric interaction between a side chain of the same polymer and a lithium ion occurs, and ionic conductivity can be exhibited. Therefore, the present invention is not limited to the lithium ion conductive inorganic solid electrolytes, which have a high ion conductivity of 10 ⁻⁴ S / cm or more in the solid state at room temperature described in these examples. Further, in the examples of the present invention, as the electronic insulating structure, only those using polyethylene mesh and glass fiber mesh have been described, but other materials, for example, a mesh of polypropylene, cellulose or the like, and not a mesh. Needless to say, the same effect can be obtained by using these nonwoven fabrics, and the present invention is not limited to the polyethylene mesh and the glass fiber mesh as the electronic insulating structure.

[0057]

As described above, according to the present invention, a lithium ion conductive solid electrolyte molded body having both high ion conductivity and high processability can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a sulfonation rate and an ionic conductivity of a lithium ion conductive solid electrolyte molded body in one example of the present invention.

FIG. 2 is a diagram showing a relationship between a sulfonation rate and an ionic conductivity of a lithium ion conductive solid electrolyte molded body in one example of the present invention.

FIG. 3 is a diagram showing the relationship between the heat treatment temperature and the ionic conductivity of a lithium ion conductive solid electrolyte molded body in one example of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Kondo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yasumasa Takeuchi 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic rubber Incorporated (72) Inventor Fusumi Masaka 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. Inventor Katsuhiro Ishikawa 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic rubber stock In-house (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01B 1/06 H01M 6/18 H01M 10/40

Claims (5)

(57) [Claims] 1. A lithium ion comprising a polymer obtained by adding sulfuric anhydride or a sulfuric anhydride-electron-donating compound complex to a carbon-carbon double bond in the molecule, and a lithium ion conductive inorganic solid electrolyte. Conductive solid electrolyte molded body. 2. The ratio of the monomer unit to which sulfuric acid anhydride or a sulfuric anhydride-electron donating compound complex is added to all the monomer units constituting the polymer is 5 mol% or more and 50% or more.
The lithium ion conductive solid electrolyte molded body according to claim 1, which is at most mol%. 3. The lithium ion conductive solid electrolyte molded article according to claim 1, wherein the lithium ion conductive inorganic solid electrolyte is an amorphous inorganic compound mainly containing sulfide. 4. The amorphous inorganic compound is synthesized from a material mainly containing lithium sulfide and silicon sulfide.
The lithium ion conductive solid electrolyte molded article described. 5. A further look including the the electrostrictive <br/> terminal insulating structure from the mesh or nonwoven fabric, the polymer and the lithium
The ion conductive inorganic solid electrolyte is the electronic insulating structure.
The lithium ion conductive solid electrolyte molded body according to claim 1, which is filled in the opening of the.