JP2010033876A - Polymer-coated solid electrolyte and all-solid secondary battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer-coated solid electrolyte which increases the mechanical strength of an all-solid lithium secondary battery to improve its battery performance. <P>SOLUTION: The polymer-coated solid electrolyte having a lithium ion conductive inorganic solid electrolyte particle coated on its surface with a lithium ion conductive polymer is used. By coating the hard surface of the solid electrolyte particle with a soft polymer, contact between the solid electrolyte particles can be improved and the mechanical strength can be increased at the same time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polymer-coated solid electrolyte and an all-solid secondary battery using the same.

  In recent years, the demand for secondary batteries such as high-performance lithium batteries used in personal digital assistants, portable electronic devices, small household power storage devices, motorcycles powered by motors, electric vehicles, hybrid electric vehicles, etc. has increased. Yes. However, there has been a problem in safety such that the electrolyte solution reacts with the electrode material due to evaporation and leakage of the electrolyte solution. In order to solve the above problem, many attempts have been made to use a solid as an electrolyte of a secondary battery.

  In a secondary battery using an electrolyte and an active material as a solid (all-solid secondary battery), an electrode is prepared by mixing and molding a powdered solid electrolyte and a powdered active material. In a powder mixture, an ion conduction path is used. In addition, many defects of the electron conduction path occur, and there is a problem that the battery performance is deteriorated. In addition, the entire electrode expands and contracts due to repeated charge / discharge cycles, resulting in poor contact between the particles, resulting in deterioration of charge / discharge characteristics.

  Patent Document 1 discloses a sheet in which an inorganic solid electrolyte powder and a thermoplastic polymer resin are combined. However, since the thermoplastic polymer resin does not have ionic conductivity, the amount that can be combined is limited. Therefore, the amount of thermoplastic polymer resin necessary for improving moldability and stability could not be combined with inorganic solid electrolyte particles (Patent Document 1).

Patent Document 2 discloses a molded body obtained by dry-mixing a sulfide-based solid electrolyte and a polymer elastic body. However, since the polymer elastic body does not have lithium ion conductivity, it lowers the lithium ion conductivity of the molded body and is a molded body obtained by dry solid-phase mixing, so the contact efficiency between particles is insufficient. Met.
Japanese Patent Laid-Open No. 04-133209 Japanese Patent Laid-Open No. 06-0776828

  An object of the present invention is to provide a polymer-coated solid electrolyte that increases the mechanical strength of a secondary battery and improves the battery performance.

According to the present invention, the following polymer-coated solid electrolyte and the like are provided.
1. A polymer-coated solid electrolyte in which the surface of a lithium ion conductive inorganic solid electrolyte is coated with a lithium ion conductive polymer.
2. 2. The polymer-coated solid electrolyte according to 1, wherein the lithium ion conductive inorganic solid electrolyte contains one or more elements selected from the group consisting of P, Si and B, Li and S.
3. A polymer-coated solid electrolyte in which a surface of a lithium ion conductive inorganic solid electrolyte is coated with a lithium ion conductive polymer, wherein a conductive auxiliary agent is dispersed in the lithium ion conductive polymer.
4). 4. The polymer-coated solid electrolyte according to 3, wherein the lithium ion conductive inorganic solid electrolyte contains one or more elements selected from the group consisting of P, Si and B, Li and S.
A positive electrode mixture comprising the polymer-coated solid electrolyte according to any one of 5.1 to 4 and a positive electrode active material.
A negative electrode mixture comprising the polymer-coated solid electrolyte according to any one of 6.1 to 4 and a negative electrode active material.
7). A positive electrode and a negative electrode;
An all-solid secondary battery comprising a solid electrolyte layer comprising the polymer-coated solid electrolyte according to 1 or 2 sandwiched between the positive electrode and the negative electrode.
8). 6. The all-solid-state secondary battery according to 6, wherein the positive electrode is composed of the positive electrode mixture according to 5.
9. The all-solid-state secondary battery according to 6 or 7, wherein the negative electrode is made of the negative electrode mixture described in 6.
10. The all-solid-state secondary battery in any one of 7-9 whose said negative electrode is a sheet form.

  ADVANTAGE OF THE INVENTION According to this invention, the polymer-coated solid electrolyte which raises the mechanical strength of a secondary battery and improves the battery performance can be provided.

  FIG. 1 is a view showing an embodiment of a polymer-coated solid electrolyte of the present invention. A polymer-coated solid electrolyte 1 (hereinafter sometimes referred to as a first polymer-coated solid electrolyte) is a lithium ion conductive inorganic solid electrolyte 10. The surface is covered with a lithium ion conductive polymer 20.

  By coating the surface of the hard solid electrolyte with a soft polymer, the contact between the solid electrolyte particles can be improved, and the mechanical strength of the battery can be improved. Further, since the coating polymer is lithium ion conductive, it is possible to prevent the ion conduction path and the electron conduction path from being damaged.

  Examples of lithium ion conductive polymers used for coating include polyethylene oxide (PEO) polymers, polyacrylonitrile (PAN) polymers, polyvinylidene fluoride (PVdF) polymers, and polymethyl methacrylate (PMMA) polymers with lithium salts. Examples include a composite polymer.

  The lithium ion conductive inorganic solid electrolyte serving as the nucleus is not particularly limited. For example, a material composed of an organic compound, an inorganic compound, or a mixture of an organic compound and an inorganic compound can be used, and preferably contains one or more elements selected from the group consisting of P, Si, and B, Li and S A lithium ion conductive inorganic solid electrolyte is used.

Among lithium ion conductive inorganic solid electrolytes, in particular, sulfide-based inorganic solid electrolytes are known to have higher ionic conductivity than other inorganic compounds, and are described in JP-A-4-202024 and the like. Can be used. Specifically, an inorganic solid electrolyte in which Li ₃ PO ₄ , a halogen, and a halogen compound are appropriately added to an inorganic solid electrolyte composed of a combination of Li ₂ S and SiS ₂ , GeS ₂ , P ₂ S ₅ , B ₂ S _3. Can be used.

  Since lithium ion conductivity is high, lithium ion conduction generated from lithium sulfide and diphosphorus pentasulfide, or lithium sulfide and simple phosphorus and simple sulfur, as well as lithium sulfide, diphosphorus pentasulfide, simple phosphorus and / or simple sulfur It is preferable to use a conductive inorganic solid electrolyte. Hereinafter, a preferable solid electrolyte will be described.

The lithium ion conductive inorganic solid electrolyte can be produced from lithium sulfide and diphosphorus pentasulfide (P ₂ S ₅ ) and / or simple phosphorus and simple sulfur. Specifically, it can be produced by melting these raw materials and then rapidly cooling them. In addition, sulfide glass obtained by treating these raw materials by a mechanical milling method (hereinafter, sometimes referred to as MM method), or a heat-treated product thereof.

As lithium sulfide, those commercially available without limitation can be used, but those having high purity are preferable as described below.
Lithium sulfide has at least a total content of lithium salt of sulfur oxide of 0.15% by mass or less, preferably 0.1% by mass or less, and a content of lithium N-methylaminobutyrate of 0.15% by mass. Hereinafter, it is preferably 0.1% by mass or less. When the total content of the lithium salt of sulfur oxide is 0.15% by mass or less, the solid electrolyte obtained by the melt quenching method or the mechanical milling method described later is a glassy electrolyte (fully amorphous). That is, when the total content of the lithium salt of sulfur oxide exceeds 0.15% by mass, the obtained electrolyte is a crystallized product from the beginning, and the ionic conductivity of this crystallized product is low. Furthermore, even if the crystallized product is subjected to the following heat treatment, the crystallized product is not changed, and a lithium ion conductive inorganic solid electrolyte having a high ion conductivity cannot be obtained.

  Further, when the content of lithium N-methylaminobutyrate is 0.15% by mass or less, a deteriorated product of lithium N-methylaminobutyrate does not deteriorate the cycle performance of the lithium battery.

  Thus, in order to obtain a high ion conductive electrolyte, it is necessary to use lithium sulfide with reduced impurities.

The method for producing lithium sulfide used for producing the high ion conductive electrolyte is not particularly limited as long as it is a method that can reduce at least the impurities.
For example, it can also be obtained by purifying lithium sulfide produced by the following method.
Among the following production methods, the method a or b is particularly preferable.
a. A method in which lithium hydroxide and hydrogen sulfide are reacted at 0 to 150 ° C. in an aprotic organic solvent to produce lithium hydrosulfide, and this reaction solution is then desulfurized at 150 to 200 ° C. -330312).
b. A method of directly producing lithium sulfide by reacting lithium hydroxide and hydrogen sulfide at 150 to 200 ° C. in an aprotic organic solvent (Japanese Patent Laid-Open No. 7-330312).
c. A method of reacting lithium hydroxide and a gaseous sulfur source at a temperature of 130 to 445 ° C. (Japanese Patent Laid-Open No. 9-283156).

  There is no restriction | limiting in particular as a purification method of the lithium sulfide obtained as mentioned above. As a preferable purification method, for example, the method described in International Publication No. WO2005 / 40039 and the like can be mentioned.

  Specifically, the lithium sulfide obtained as described above is washed at a temperature of 100 ° C. or higher using an organic solvent. The organic solvent used for washing is preferably an aprotic polar solvent, and more preferably, the aprotic organic solvent used for lithium sulfide production and the aprotic polar organic solvent used for washing are the same. .

  Examples of the aprotic polar organic solvent preferably used for washing include aprotic polar organic compounds such as amide compounds, lactam compounds, urea compounds, organic sulfur compounds, cyclic organophosphorus compounds, Or it can use suitably as a mixed solvent. In particular, N-methyl-2-pyrrolidone (NMP) is selected as a good solvent.

  The amount of the organic solvent used for washing is not particularly limited, and the number of times of washing is not particularly limited, but is preferably 2 or more. Cleaning is preferably performed under an inert gas such as nitrogen or argon.

  The washed lithium sulfide is dried at a temperature equal to or higher than the boiling point of the organic solvent used for washing for 5 minutes or more, preferably about 2 to 3 hours or more under an inert gas stream such as nitrogen under normal pressure or reduced pressure. Thus, lithium sulfide suitably used in the present invention can be obtained.

P ₂ S ₅ can be used without particular limitation as long as it is industrially manufactured and sold. In place of P ₂ S ₅ , elemental phosphorus (P) and elemental sulfur (S) in a corresponding molar ratio can also be used. Simple phosphorus (P) and simple sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

  In the present invention, as the solid electrolyte, both a glassy solid electrolyte and a solid electrolyte containing a crystal component can be used. The type should be selected according to the required characteristics. Both may be used.

The mixing molar ratio of the lithium sulfide to diphosphorus pentasulfide or simple phosphorus and simple sulfur is usually 50:50 to 80:20, preferably 60:40 to 75:25.
Particularly preferably, it is about Li ₂ S: P ₂ S ₅ = 68: 32 to 74:26 (molar ratio).

  Examples of the method for producing a sulfide glass that is a glassy electrolyte include a melt quenching method and a mechanical milling method.

In the case of the melt quenching method, a predetermined amount of P ₂ S ₅ and Li ₂ S are mixed in a mortar, and the pellets are placed in a carbon-coated quartz tube and sealed in a vacuum. After reacting at a predetermined reaction temperature, the glass is put into ice and quenched to obtain a sulfide glass.

  The reaction temperature at this time is preferably 400 ° C to 1000 ° C, more preferably 800 ° C to 900 ° C. Moreover, reaction time becomes like this. Preferably it is 0.1 to 12 hours, More preferably, it is 1 to 12 hours. The quenching temperature of the reaction product is usually 10 ° C. or lower, preferably 0 ° C. or lower, and the cooling rate is about 1 to 10,000 K / sec, preferably 1 to 1000 K / sec.

In the case of the MM method, sulfide glass is obtained by mixing a predetermined amount of P ₂ S ₅ and Li ₂ S in a mortar and reacting for a predetermined time by a mechanical milling method.

  The mechanical milling method using the above raw materials can be reacted at room temperature. According to the MM method, since a glassy electrolyte can be produced at room temperature, there is an advantage that a raw material is not thermally decomposed and a glassy electrolyte having a charged composition can be obtained. Further, the MM method has an advantage that the glassy electrolyte can be made into fine powder simultaneously with the production of the glassy electrolyte.

  Although various types of pulverization methods can be used for the MM method, it is particularly preferable to use a planetary ball mill. The planetary ball mill can efficiently generate very high impact energy by rotating the platform while the pot rotates.

  Although the rotation speed and rotation time of the MM method are not particularly limited, the faster the rotation speed, the faster the glassy electrolyte production rate, and the longer the rotation time, the higher the conversion rate of the raw material into the glassy electrolyte.

The electrolyte thus obtained is a glassy electrolyte and usually has an ionic conductivity of about 1.0 × 10 ^{−5 to} 8.0 × 10 ⁻⁴ (S / cm).

  As conditions for the MM method, for example, when a planetary ball mill is used, the rotational speed may be set to several tens to several hundreds of revolutions / minute, and the treatment may be performed for 0.5 hours to 100 hours.

  Although specific examples of the sulfide glass by the melt quenching method and the MM method have been described above, manufacturing conditions such as temperature conditions and processing time can be appropriately adjusted according to the equipment used.

  Thereafter, the obtained sulfide glass is heat-treated at a predetermined temperature to produce a solid electrolyte containing a crystal component.

  The heat treatment temperature for producing such a solid electrolyte is preferably 190 ° C to 340 ° C, more preferably 195 ° C to 335 ° C, and particularly preferably 200 ° C to 330 ° C. When the temperature is lower than 190 ° C., it may be difficult to obtain a crystal with high ion conductivity. When the temperature is higher than 340 ° C., a crystal with low ion conductivity may be generated.

  The heat treatment time is preferably 3 to 240 hours, particularly preferably 4 to 230 hours, when the temperature is 190 ° C or higher and 220 ° C or lower. When the temperature is higher than 220 ° C and not higher than 340 ° C, 0.1 to 240 hours are preferable, 0.2 to 235 hours are particularly preferable, and 0.3 to 230 hours are more preferable. If the heat treatment time is shorter than 0.1 hour, it may be difficult to obtain a crystal with high ion conductivity. If the heat treatment time is longer than 240 hours, a crystal with low ion conductivity may be formed.

The lithium ion conductive inorganic solid electrolyte containing the crystal component thus obtained usually has an ionic conductivity of about 7.0 × 10 ^{−4 to} 5.0 × 10 ⁻³ (S / cm). It is.

This lithium ion conductive inorganic solid electrolyte has 2θ = 17.8 ± 0.3 deg, 18.2 ± 0.3 deg, 19.8 ± 0.3 deg, X-ray diffraction (CuKα: λ = 1.5418４), 21.8 ± 0.3 deg, 23.8 ± 0.3 deg, 25.9 ± 0.3 deg
It is preferable to have diffraction peaks at g, 29.5 ± 0.3 deg, 30.0 ± 0.3 deg. A solid electrolyte having such a crystal structure has extremely high lithium ion conductivity.

  The first polymer-coated solid electrolyte is produced by mechanically mixing the above-described lithium ion conductive polymer and lithium ion conductive inorganic solid electrolyte using a mechanical milling method using a mechano-fusion, a planetary ball mill, or the like. be able to.

In addition to the above method, the first polymer-coated solid electrolyte is obtained by treating a lithium ion conductive inorganic solid electrolyte with a solvent in which a lithium ion conductive polymer is dissolved by a dip method, a spray drying method, etc., and removing the solvent by drying. Can be manufactured.
The solvent for dissolving the polymer is not particularly limited, and is preferably a solvent that does not react with the lithium ion conductive polymer (for example, an alkane solvent or an aromatic solvent).

  FIG. 2 is a view showing another embodiment of the polymer-coated solid electrolyte of the present invention. The polymer-coated solid electrolyte 2 (hereinafter sometimes referred to as a second polymer-coated solid electrolyte) The same as the polymer-coated solid electrolyte 1 except that the conductive additive 30 is dispersed in the polymer.

By dispersing a conductive additive in the coating polymer of the polymer-coated solid electrolyte, the electronic conductivity of the electrolyte surface can be increased.
Examples of the conductive assistant include conductive substances such as acetylene black, carbon black, and carbon nanotubes, conductive polymers such as polyaniline, polyacetylene, and polypyrrole, or a mixture thereof, graphite, and metal powder. it can.

  The production method of the second polymer-coated solid electrolyte is the same as the production method of the first polymer-coated solid electrolyte, except that a polymer in which a conductive additive is dispersed in advance is used.

As described above, since the second polymer-coated solid electrolyte has high electronic conductivity, it is preferably mixed with the positive electrode active material or the negative electrode active material to form a positive electrode mixture or a negative electrode mixture, respectively.
The electrolyte used for the positive electrode mixture or the negative electrode mixture may be a first polymer-coated solid electrolyte.

When the polymer-coated solid electrolyte of the present invention and the positive electrode active material are mixed to form a positive electrode mixture, the positive electrode active material is a layered transition metal represented by LiXO ₂ (X: Co, Ni, Mn, or a mixture thereof). Oxides, spinel oxides represented by LiX ₂ O ₄ (X: Mn, V, mixtures thereof, etc.), olivine-type phosphate compounds represented by LiXPO ₄ (X: Fe, Co, Ni, etc.), Examples thereof include metal sulfides represented by XS ₂ (X: Ti, Mo, Fe, etc.).

  The positive electrode mixture of the present invention can be produced by mixing the positive electrode active material and the polymer-coated solid electrolyte at a predetermined ratio. As a ratio, it can use in the ratio of 20 wt%-95 wt% as solid weight% (wt%) of a positive electrode active material. More preferably, it is 50 wt%-90 wt%, and a more suitable ratio is 60 wt%-80 wt%. As a method of mixing, in addition to a method of mixing the dried powder with an agate mortar or the like, a method of directly adding to an organic solvent and mixing can be used.

When the polymer-coated solid electrolyte of the present invention and the negative electrode active material are mixed to form a negative electrode mixture, commercially available negative electrode active materials can be used without particular limitation, and carbon materials, Sn metals, and In metals can be used. Etc. can be used suitably. Specifically, natural graphite, various graphites, metal powders such as Sn, Si, Al, Sb, Zn, and Bi, metals such as Sn ₅ Cu ₆ , Sn ₂ Co, Sn ₂ Fe, Ti—Sn, and Ti—Si Examples include alloy powder, oxide (Li4 / 3Ti5 / 3O), nitride (LiCoN), and other amorphous alloys and plating alloys. Although there is no restriction | limiting in particular regarding a particle size, A thing with an average particle diameter of several micrometers-80 micrometers can be used suitably.

  The negative electrode mixture of the present invention can be prepared by mixing the above-described negative electrode active material and polymer-coated solid electrolyte at a predetermined ratio. As a ratio, it can be used in the ratio of 30 wt%-90 wt% as solid weight% (wt%) of a positive electrode active material. More preferably, it is 40 wt%-80 wt%, and a more suitable ratio is 50 wt%-80 wt%. As a method of mixing, in addition to a method of mixing the dried powder with an agate mortar or the like, a method of directly adding to an organic solvent and mixing can be used.

FIG. 3 is a schematic cross-sectional view showing an embodiment of an all solid state secondary battery according to the present invention.
In the all-solid-state secondary battery 3, a solid electrolyte layer 50 is sandwiched between a pair of electrodes composed of a positive electrode 40 and a negative electrode 60 made of the positive electrode mixture of the present invention. Current collectors 70 and 72 are provided on the positive electrode 40 and the negative electrode 60, respectively.

The solid electrolyte layer 50 is preferably made of the first polymer-coated solid electrolyte of the present invention.
The solid electrolyte layer 50 can be manufactured by depositing a particulate lithium ion conductive inorganic solid electrolyte by, for example, a blast method or an aerosol deposition method. Also, a lithium ion conductive inorganic solid electrolyte can be formed by a cold spray method, a sputtering method, a vapor phase deposition method (CVD), a thermal spraying method, or the like.
Further, there is a method in which a solution in which a lithium ion conductive inorganic solid electrolyte is mixed with a solvent or a binder (such as a binder or a polymer compound) is applied and applied, and then the solvent is removed to form a film. Also, the solid electrolyte itself, solid electrolyte and binder (binder, polymer compound, etc.) and support (materials and compounds to reinforce the strength of the solid electrolyte layer and prevent short circuit of the solid electrolyte itself) are mixed -It is also possible to form a film by pressing the combined electrolyte under pressure.

Although the solvent used for film-forming of a solid electrolyte layer will not be specifically limited if it does not have a bad influence on the performance of a solid electrolyte, For example, a non-aqueous solvent is mentioned.
Examples of the non-aqueous solvent include solvents used in electrolyte solutions such as dry heptane, toluene, hexane, tetrahydrofuran (THF), N methylpyrrolidone, acetonitrile, dimethoxyethane, and dimethyl carbonate, and preferably have a water content. The solvent is 100 ppm or less, more preferably 50 ppm or less.

As the binder, a thermoplastic resin or a thermosetting resin can be used. For example, polysiloxane, polyalkylene glycol, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer ( FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer ( ETFE resin), polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene -Chlorotrifluoroethylene copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer (Na ⁺⁾ ion crosslinked product of polymer or the material, ethylene - (Na ⁺⁾ ion crosslinked product of methacrylic acid copolymer or the materials, ethylene - methyl acrylate copolymer or (Na ⁺⁾ ion crosslinked body, ethylene - can be given (Na ⁺⁾ ion crosslinked product of methyl methacrylate copolymer or the material.

  Among these, polysiloxane, polyalkylene glycol, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) are preferable.

  The positive electrode 40 is preferably made of the positive electrode mixture of the present invention, and can be produced by forming the positive electrode mixture of the present invention in a film shape on at least a part of the current collector 70. As a film forming method, in addition to a method of forming a mixed liquid composed of a positive electrode mixture and a solvent, for example, a blast method, an aerosol deposition method, a cold spray method, a sputtering method, a vapor phase growth method, a pressure press A method or a thermal spraying method can also be used. By forming a film by such a method, the porosity of the positive electrode can be further reduced, and electron conduction, electron exchange, and ion conduction can be improved.

  In the case of forming a positive electrode by applying a mixed liquid composed of a positive electrode mixture and a solvent, the mixed liquid does not have the positive electrode mixture of the present invention dissolved in the solvent. Since the specific gravity of the positive electrode mixture of the present invention is usually larger than the specific gravity of the solvent, it is usually precipitated in the above mixed solution, but when forming the positive electrode, the positive electrode mixture is uniformly dispersed by stirring or the like. It is preferable to use a mixed liquid.

  The solvent used in the mixed solution is preferably a solvent having low reactivity with the positive electrode mixture, but by treating the positive electrode mixture surface so that the positive electrode mixture does not react with the solvent, for example, by coating the surface of the positive electrode mixture, A solvent having high reactivity with the material can also be used.

The solvent is preferably an organic solvent, more preferably a hydrocarbon organic solvent, such as hexane, heptane, toluene, xylene, decalin, and the like.
Of these solvents, hexane, toluene, and xylene, which are low-boiling solvents, are preferable in consideration of the drying process after coating, but it is difficult to use a low-boiling solvent having a high evaporation rate in consideration of maintaining the mixed liquid. , Toluene, xylene and the like are preferable.

  The solvent used in the mixed solution is preferably dehydrated to reduce the water content. The water content of the solvent is usually 30 ppm or less, preferably 10 ppm or less, more preferably 1.0 ppm or less.

You may further add a binder to the liquid mixture which consists of a positive electrode compound material and a solvent.
The binder is not particularly limited as long as the reactivity with the positive electrode mixture is low, preferably a thermoplastic resin and a thermosetting resin, more preferably polysiloxane, polyalkylene glycol, polytetrafluoroethylene (PTFE), Polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), styrene butadiene rubber / carboxymethyl cellulose (SBR / CMC), polyethylene oxide (PEO), branched PEO, polyphenylene oxide (PPO), PEO-PPO copolymer, branched PEO -PPO copolymer, alkylborane-containing polyether.
The binder is particularly preferably SBR or polyalkylene glycol from the viewpoint of ease of sheet formation, prevention of increase in interface resistance and prevention of reduction in charge / discharge capacity.

The negative electrode 60 can be produced in the same manner as the positive electrode 40.
The negative electrode 60 is preferably in the form of a sheet. By making the negative electrode into a sheet, it is possible to insert and desorb lithium.

The current collectors 70 and 72 include a plate-like body or foil-like body made of copper, magnesium, stainless steel, titanium, iron, cobalt, nickel, zinc, aluminum, germanium, indium, lithium, or an alloy thereof. Can be used.
The current collectors 70 and 72 may be the same as or different from each other. For example, a copper foil may be used for the current collector 70, and an aluminum foil may be used for the current collector 72.

The all-solid-state secondary battery can be manufactured by bonding and joining the battery members described above. As a method of joining, there are a method of laminating each member, pressurizing and pressure bonding, a method of pressing through two rolls (roll to roll), and the like.
Moreover, you may join to the joining surface through the active material which has ion conductivity, and the adhesive material which does not inhibit ion conductivity.
In joining, heat fusion may be performed as long as the crystal structure of the solid electrolyte does not change.

The polymer-coated solid electrolyte of the present invention can be used for an all-solid secondary battery.
The all-solid-state secondary battery of the present invention can be used as a battery for a portable information terminal, a portable electronic device, a small electric power storage device for home use, a motorcycle using a motor as a power source, an electric vehicle, a hybrid electric vehicle, or the like.

It is a figure which shows one Embodiment of the polymer covering solid electrolyte of this invention. It is a figure which shows other embodiment of the polymer covering solid electrolyte of this invention. It is a schematic sectional drawing which shows one Embodiment of the all-solid-state lithium battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Polymer-coated solid charge chamber 3 All-solid-state secondary battery 10 Lithium ion conductive inorganic solid electrolyte 20 Lithium conductive polymer 30 Conductive auxiliary agent 40 Positive electrode 50 Solid electrolyte layer 60 Negative electrode 70,72 Current collector

Claims (10)

  A polymer-coated solid electrolyte in which the surface of a lithium ion conductive inorganic solid electrolyte is coated with a lithium ion conductive polymer.   The polymer-coated solid electrolyte according to claim 1, wherein the lithium ion conductive inorganic solid electrolyte contains one or more elements selected from the group consisting of P, Si and B, Li and S. A polymer-coated solid electrolyte in which the surface of a lithium ion conductive inorganic solid electrolyte is coated with a lithium ion conductive polymer,
A polymer-coated solid electrolyte in which a conductive additive is dispersed in the lithium ion conductive polymer.   The polymer-coated solid electrolyte according to claim 3, wherein the lithium ion conductive inorganic solid electrolyte contains one or more elements selected from the group consisting of P, Si and B, Li and S.   A positive electrode mixture comprising the polymer-coated solid electrolyte according to claim 1 and a positive electrode active material.   A negative electrode mixture comprising the polymer-coated solid electrolyte according to claim 1 and a negative electrode active material. A positive electrode and a negative electrode;
An all-solid-state secondary battery comprising a solid electrolyte layer comprising the polymer-coated solid electrolyte according to claim 1 or 2 sandwiched between the positive electrode and the negative electrode.   The all-solid-state secondary battery according to claim 6, wherein the positive electrode is made of the positive electrode mixture according to claim 5.   The all-solid-state secondary battery according to claim 6 or 7, wherein the negative electrode is made of the negative electrode mixture according to claim 6.   The all-solid-state secondary battery according to claim 7, wherein the negative electrode has a sheet shape.

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