JP5001621B2 - Solid electrolyte and solid secondary battery using the same - Google Patents

Description

  The present invention relates to a solid electrolyte and a solid secondary battery using the same.

In recent years, there has been an increase in 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. ing.
As the applications used expand, further improvements in safety and higher performance of secondary batteries are required.
As a method for ensuring the safety of the lithium battery, it is effective to use an inorganic solid electrolyte instead of the organic solvent electrolyte.

  Inorganic solid electrolytes are generally nonflammable by nature and are safer materials than commonly used organic solvent electrolytes. Therefore, development of a lithium solid state secondary battery having high safety using a solid electrolyte is desired.

In Patent Document 1, a glass ceramic is produced by firing a lithium-phosphorous sulfide glass produced from lithium sulfide (Li ₂ S) and diphosphorus pentasulfide (P ₂ S ₅ ). It is shown for use in a solid electrolyte layer. A lithium secondary solid battery using this glass ceramic as a solid electrolyte layer can obtain good rate characteristics.

WO2005 / 078740 pamphlet

However, the above-mentioned solid secondary battery has a problem in that, when charging and discharging are repeated, the glass ceramics, which are solid electrolytes, expand and contract each time, creating a space in which the glass ceramic particles do not adhere to each other, resulting in poor cycle characteristics. It was.
An object of the present invention is to provide a solid secondary battery excellent in rate characteristics and cycle characteristics.

The present inventors have found that a solid secondary battery excellent in both rate characteristics and cycle characteristics can be obtained by using a mixture of glass and glass ceramic as a solid electrolyte.
According to the present invention, the following solid electrolyte and a solid secondary battery using the same are provided.
1. A solid electrolyte comprising a mixture of 10 to 90% by weight of sulfide-based glass and 90 to 10% by weight of sulfide-based glass ceramic.
2. A solid secondary battery comprising: a positive electrode; a negative electrode; and a solid electrolyte layer comprising the solid electrolyte according to 1 sandwiched between the positive electrode and the negative electrode.
3. 3. The solid secondary battery according to 2, wherein the negative electrode is made of graphite or lithium metal.

  According to the present invention, a solid secondary battery excellent in rate characteristics and cycle characteristics can be provided.

The solid secondary battery of the present invention includes a positive electrode, a negative electrode, and a solid electrolyte layer sandwiched between the positive electrode and the negative electrode.
The solid electrolyte layer is made of a mixture of sulfide-based glass and sulfide-based glass ceramic.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a solid secondary battery according to the present invention.
In the all-solid-state secondary battery 1, a solid electrolyte layer 20 is sandwiched between a pair of electrodes including a positive electrode 10 and a negative electrode 30. Current collectors 40 and 42 are provided on the positive electrode 10 and the negative electrode 30, respectively.

The solid electrolyte layer 20 is composed of a mixture of sulfide glass and glass ceramic. Since glass is softer than glass ceramic, the mixture is softer than that composed solely of glass ceramic, and therefore the overall hardness of the solid electrolyte layer 20 is reduced.
Softer glass enters between the glass-ceramic particles, and the glass and glass-ceramic particles are in close contact with each other, and peeling due to discharge is less likely to occur. As a result, the battery performance is not deteriorated even after many times of charge and discharge, and good cycle characteristics can be obtained.

  The mixing ratio (weight ratio) between the sulfide-based glass and the glass ceramic is preferably 10 to 90:90 to 10, more preferably 20 to 80:80 to 20.

  Furthermore, since the solid electrolyte layer 20 is composed of a mixture obtained by mixing a sulfide glass ceramic with a sulfide glass having a relatively high ionic conductivity, the solid electrolyte layer 20 is also excellent in rate characteristics.

A sulfide-based inorganic solid electrolyte is known to have higher ionic conductivity than other inorganic compounds, and an inorganic solid electrolyte described in JP-A-4-202024 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.

The lithium-phosphorus sulfide electrolyte suitably used in the present invention includes lithium sulfide and diphosphorus pentasulfide (P ₂ S ₅ ), or lithium sulfide and simple phosphorus and simple sulfur, as well as lithium sulfide and phosphorus pentasulfide. Can be produced from simple phosphorus and / or simple sulfur.

  As lithium sulfide for producing the above sulfide-based electrolyte, those commercially available without particular limitation can be used, but those having high purity are preferred.

  Preferably, the lithium sulfide has a total content of lithium salts of sulfur oxides of 0.15% by mass or less, more preferably 0.1% by mass or less, and a content of lithium N-methylaminobutyrate of 0.1%. It is 15 mass% or less, More preferably, it is 0.1 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 becomes 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 may be a crystallized product from the beginning, and the ionic conductivity of the crystallized product is low. Furthermore, even if this crystallized product is subjected to a heat treatment, the crystallized product is not changed, and there is a possibility that 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.

  When lithium sulfide with reduced impurities is used, a high ion conductive electrolyte can be obtained.

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 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 refinement | purification method of lithium sulfide. As a preferable purification method, for example, the method described in International Publication No. WO2005 / 40039 and the like can be mentioned.

  Specifically, lithium sulfide 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 moreover, the aprotic organic solvent used for the production of lithium sulfide and the aprotic polar organic solvent used for washing are more preferably the same. preferable.

  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, and the like. 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 that is suitably used 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.

The mixing molar ratio of lithium sulfide to diphosphorus pentasulfide and / 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 a method for producing a glassy electrolyte include a melt quenching method and a mechanical milling method (MM 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 constant reaction temperature, the glass is put into ice and rapidly cooled 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 reactant is usually 10 ° C. or less, preferably 0 ° C. or less, and the cooling rate is usually 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 them for a certain 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.

  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.

  The sulfide glass thus obtained is fired to obtain a glass ceramic. The firing temperature 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. Moreover, in the case of the temperature higher than 220 degreeC and 340 degrees C or less, 0.1 to 240 hours are preferable, especially 0.2 to 235 hours are preferable, and also 0.3 to 230 hours are preferable. If the heat treatment time is shorter than 0.1 hour, a crystal having high ion conductivity may be difficult to obtain, and if it is longer than 240 hours, a crystal having low ion conductivity may be generated.

  Crystalline sulfide glass ceramics obtained by heat-treating sulfide glass are 2θ = 17.8 ± 0.3 deg, 18.2 ± 0.3 deg, X-ray diffraction (CuKα: λ = 1.5418１．５), Diffraction peaks at 19.8 ± 0.3 deg, 21.8 ± 0.3 deg, 23.8 ± 0.3 deg, 25.9 ± 0.3 deg, 29.5 ± 0.3 deg, 30.0 ± 0.3 deg It is preferable to have. A solid electrolyte having such a crystal structure has extremely high lithium ion conductivity.

The fixed electrolyte layer can be produced, for example, by forming a film of a mixture of particulate lithium / phosphorous sulfide glass and glass ceramic by a blast method or an aerosol deposition method. Also, a lithium ion conductive solid material can be formed by a cold spray method, a sputtering method, a vapor deposition method (CVD), a thermal spraying method, or the like.
Further, there is a method in which a solution in which a solid electrolyte is mixed with a solvent and a binder (binder, polymer compound, etc.) 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.
Blasting and aerosol deposition are preferred because they can be formed in a temperature range that does not change the state of the solid electrolyte under simple equipment and room temperature conditions.

As a material for the positive electrode, those used as a positive electrode active material in the battery field can be used. For example, in the sulfide system, titanium sulfide (TiS ₂ ), molybdenum sulfide (MoS ₂ ), iron sulfide (FeS, FeS ₂ ), copper sulfide (CuS), nickel sulfide (Ni ₃ S ₂ ), and the like can be used. Preferably, TiS ₂ can be used.
In the oxide system, bismuth oxide (Bi ₂ O ₃ ), bismuth leadate (Bi ₂ Pb ₂ O ₅ ), copper oxide (CuO), vanadium oxide (V ₆ O ₁₃ ), lithium cobalt oxide (LiCoO ₂₎ ), Lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and other metal acid lithium can be used. It is also possible to use a mixture of these. Preferably, lithium cobaltate can be used.
In addition to the above, niobium selenide (NbSe ₃ ) can be used. The surface of the lithium metalate may be coated with a coating material in order to improve rate characteristics.
Examples of the coating material include spinel titanate, tantalum oxide, niobium oxide, and the like. Specifically, Li ₄ Ti ₅ O ₁₂ , LiTaO ₃ , LiNbO ₃ , LiAlO ₂ , Li ₂ ZrO ₃ , Li ₂ WO ₄ , Li ₂ TiO ₃ , Li ₂ B ₄ O ₇ , Li ₃ PO ₄ , Li ₂ MoO ₄ , LiBO _{2 and the} like.

Examples of the method for coating the surface of the lithium metal oxide particles with the coating material include spray coating. For example, the surface of lithium metal oxide is spray-coated with a solution of ethanol or the like in which the coating material is dispersed, and this is heated to obtain lithium metal oxide particles coated with the coating material.
The thickness of the coating layer coated with the lithium metal oxide is usually 0.5 to 50 nm, preferably 1 to 40 nm.

As the material for the negative electrode, those used as the negative electrode active material in the battery field can be used. For example, carbon materials, specifically artificial graphite, graphite carbon fiber, resin-fired carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-fired carbon, polyacene, pitch-based carbon Examples thereof include fibers, vapor-grown carbon fibers, natural graphite, and non-graphitizable carbon. Alternatively, a mixture thereof may be used.
Also, an alloy in combination with a metal itself such as metallic lithium, metallic indium, metallic aluminum, metallic silicon, or another element or compound can be used as the negative electrode material.
Desirably, the negative electrode is made of graphite (artificial graphite) or lithium metal.

  In addition, in the positive electrode and negative electrode materials (polar materials) of the solid secondary battery, in order to improve the ionic conductivity in addition to the electronic conductivity, the particles of the polar materials are in close contact with each other, and the junction points and surfaces between the particles are determined. It is important to ensure that there are many ion conduction paths. Therefore, a method is used in which an ion conductive active material such as an electrolyte is mixed to make an electrode material. As the ion conductive active material, lithium / phosphorous sulfide glass and glass ceramic used in the solid electrolyte can be used. In addition, the smaller the space generated in the gap between the polar material particles (the ratio of the volume of the polar material particles to the volume of the polar material particles: the porosity), the denser the polar material layer is and the higher the ionic conductivity.

  Further, in the electrode material, an electrically conductive substance may be appropriately added as a conductive auxiliary agent so that electrons move smoothly in the positive electrode and the negative electrode active material. The electrically conductive substance is not particularly limited, but a conductive substance such as acetylene black, carbon black, or carbon nanotube or a conductive polymer such as polyaniline, polyacetylene, or polypyrrole is used alone or in combination. Can do.

The positive electrode and the negative electrode can be produced by forming the above-mentioned electrode material (positive electrode material or negative electrode material) in a film shape on at least a part of the current collector. As a film forming method, the same method as that for the solid electrolyte layer can be used. Examples thereof include a blast method, an aerosol deposition method, a cold spray method, a sputtering method, a vapor phase growth method, and a thermal spraying method. By forming a film by such a method, the porosity of the electrode material layer can be further reduced, and the ionic conductivity can be improved.
Blasting and aerosol deposition are preferred because they can be formed in a temperature range that does not change the crystal state of the electrolyte under simple equipment and room temperature conditions.

  As the current collector material, a plate or foil made of copper, magnesium, stainless steel, titanium, iron, cobalt, nickel, zinc, aluminum, germanium, indium, lithium, or an alloy thereof is used. it can.

This solid 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.

[Production Example 1]
(1) Production of lithium sulfide (Li ₂ S) In a 10 liter autoclave equipped with a stirring blade, N-methyl-2-pyrrolidone (NMP) 3326.4 g (33.6 mol) and lithium hydroxide 287.4 g (12 mol) ) And heated to 300 rpm and 130 ° C. After the temperature rise, hydrogen sulfide was blown into the liquid at a supply rate of 3 liters / minute for 2 hours. Subsequently, this reaction solution was heated in a nitrogen stream (200 cc / min) to dehydrosulfide a part of the reacted hydrogen sulfide. As the temperature increased, water produced as a by-product due to the reaction between hydrogen sulfide and lithium hydroxide started to evaporate, but this water was condensed by the condenser and extracted out of the system. While water was distilled out of the system, the temperature of the reaction solution rose, but when the temperature reached 180 ° C., the temperature increase was stopped and the temperature was kept constant. After the dehydrosulfurization reaction was completed (about 80 minutes), the reaction was completed to obtain lithium sulfide.

(2) Purification of lithium sulfide After decanting NMP in the 500 mL slurry reaction solution (NMP-lithium sulfide slurry) obtained in (1) above, 100 mL of dehydrated NMP was added and stirred at 105 ° C. for about 1 hour. did. NMP was decanted at that temperature. Further, 100 mL of NMP was added, stirred at 105 ° C. for about 1 hour, NMP was decanted at that temperature, and the same operation was repeated a total of 4 times. After completion of the decantation, lithium sulfide was dried at 230 ° C. (temperature higher than the boiling point of NMP) under a nitrogen stream for 3 hours under normal pressure. The impurity content in the obtained lithium sulfide was measured.

Incidentally, lithium sulfite _(Li 2 _SO 3), the content of each sulfur oxide lithium sulfate _(Li 2 SO ₄₎ and lithium thiosulfate _{(Li 2 S 2 O 3)} , and N- methylamino acid lithium (LMAB) Was quantified by ion chromatography. As a result, the total content of sulfur oxides was 0.13% by mass, and LMAB was 0.07% by mass.

(3) Manufacture of Lithium Phosphorus Sulfide Glass A mixture of Li ₂ S and P ₂ S ₅ (manufactured by Aldrich) manufactured as described above in a molar ratio of 70:30 to about 1 g and alumina having a diameter of 10 mm Ten balls made in a 45 mL alumina container were placed in a planetary ball mill (Fritsch: Model No. P-7) in nitrogen at room temperature (25 ° C.) at a rotation speed of 370 rpm and mechanical for 20 hours. Milling was performed to obtain a lithium / phosphorous sulfide glass as a white yellow powder. This powder was confirmed to be glass because the X-ray spectrum chart obtained by powder X-ray diffraction measurement (CuKα: λ = 1,5418Å) showed a broad shape peculiar to the amorphous body. .

(4) Manufacture of glass ceramic The lithium phosphosulfide glass obtained in (3) was fired in nitrogen at a temperature range from room temperature (25 ° C) to 260 ° C to obtain a glass ceramic. About this powder, 2θ = 17.8 deg, 18.2 deg, 19.8 deg, 21.8 deg, 23.8 deg, 25 in the X-ray spectrum chart obtained by powder X-ray diffraction measurement (CuKα: λ = 1, 5418Å). Since diffraction peaks were observed at .9 deg, 29.5 deg, and 30.0 deg, it was confirmed to be a glass ceramic.

[Example 1]
A negative electrode material constituting the negative electrode was produced by mixing carbon graphite (manufactured by TIMCAL, SFG-15) and the glass ceramic of Production Example 1 (4) at a mass ratio of 50:50. A positive electrode material constituting the positive electrode was produced by mixing lithium cobaltate and the glass ceramic of Production Example 1 (4) at a mass ratio of 60:40. The solid electrolyte material constituting the solid electrolyte was produced by mixing the lithium phosphosulfide glass of Production Example 1 (3) and the glass ceramic of Production Example 1 (4) at a weight ratio of 75:25. Then, using a commercially available pellet molding machine, the negative electrode material (10 mg), the solid electrolyte material (150 mg), and the positive electrode material (20 mg) were sequentially placed in the pellet molding machine, and a pressure of 20 t / cm ^{2 was} sequentially applied to the negative electrode, A measurement cell for performance evaluation of three layers of a solid electrolyte and a positive electrode was manufactured.

Rate characteristics were evaluated by charging and discharging the measurement cell with a constant current at a current density of 5 mA / cm ² . At that time, the upper limit voltage of charging / discharging was 4.2V, and the lower limit voltage was 1.0V. That is, at the time of charging, when the voltage of the measuring cell increased to 4.2 V, the battery started discharging, and when the voltage reached 1.0 V, the evaluation was finished. As a result, this measurement cell was able to be charged / discharged at 5 mA / cm ² , and thus was judged to have excellent rate characteristics.
In addition, the cycle characteristics were evaluated by repeating charge and discharge of this measurement cell at a constant current at a current density of 0.1 mA / cm ² . At that time, the upper limit voltage of charging / discharging was 4.2V, and the lower limit voltage was 1.0V. That is, at the time of charging, when the voltage of the measuring cell increased to 4.2V, the cell shifted to discharging, and the cycle characteristics were evaluated by the change in discharge capacity obtained up to the point of reaching 1.0V. The cycle characteristics were evaluated by indicating the percentage of the discharge capacity obtained at the 11th time to the discharge capacity obtained at the first time as a percentage. The measurement results are shown in Table 1.

[Example 2]
A solid secondary battery in the same manner as in Example 1 except that the weight ratio of the lithium / phosphorous sulfide glass, which is a solid electrolyte material, and the glass ceramic was changed to lithium / phosphorous sulfide glass: glass ceramic = 50: 50. The battery characteristics were measured. The measurement results are shown in Table 1.

[Example 3]
A solid secondary battery in the same manner as in Example 1 except that the weight ratio of the lithium / phosphorous sulfide glass, which is a solid electrolyte material, and the glass ceramic is lithium / phosphorous sulfide glass: glass ceramic = 25: 75. The battery characteristics were measured. The measurement results are shown in Table 1.

[Comparative Example 1]
A solid secondary battery was produced in the same manner as in Example 1 except that the solid electrolyte material was glass ceramic (lithium / phosphorous sulfide glass: glass ceramic = 0: 100), and the battery characteristics were measured. . The measurement results are shown in Table 1. The rate characteristics were excellent, but the cycle characteristics were inferior.

[Comparative Example 2]
A solid secondary battery was produced in the same manner as in Example 1 except that the solid electrolyte material was all glass (lithium / phosphorous sulfide glass: glass ceramic = 100: 0), and the battery characteristics were measured. The measurement results are shown in Table 1. The cycle characteristics were excellent, but the rate characteristics were inferior.

  The solid 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 schematic sectional drawing which shows one Embodiment of the solid secondary battery which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 All-solid-state secondary battery 10 Positive electrode 20 Solid electrolyte layer 30 Negative electrode 40,42 Current collector

Claims (3)

A solid electrolyte for use in a lithium solid state secondary battery comprising a mixture of 10 to 90% by weight of sulfide-based glass particles and 90 to 10% by weight of sulfide-based glass ceramic particles. A positive electrode, a negative electrode,
The lithium solid state secondary battery which has the solid electrolyte layer which consists of a solid electrolyte of Claim 1 clamped by the said positive electrode and a negative electrode. The lithium solid state secondary battery according to claim 2, wherein the negative electrode is made of graphite or lithium metal.

Images