One aspect of the present invention is a solid electrolyte containing lithium, phosphorus, sulfur, halogen, and tin as constituent elements and having a crystal structure.

One aspect of the present invention is a solid electrolyte containing lithium, phosphorus, sulfur, halogen, and tin as constituent elements and having a crystal structure.

According to a method for producing a solid electrolyte that contains a lithium atom, a sulfur atom, a phosphorus atom and a halogen atom, including mixing a complexing agent and a solid electrolyte raw material, a solid electrolyte having a high ionic conductivity is provided using a liquid-phase method.

A solid electrolyte includes lithium, phosphorus, sulfur, and halogen, in which, when the solid electrolyte is measured by TG-MS, a first peak derived from cyclic sulfur appears in a temperature range of 170° C. or higher and lower than 250° C., a second peak derived from the cyclic sulfur appears in a temperature range of 250° C. or higher and lower than 300° C., and a peak intensity P1 of the first peak is higher than a peak intensity P2 of the second peak.

A solid electrolyte includes lithium, phosphorus, sulfur, and halogen, in which, when the solid electrolyte is measured by TG-MS, a first peak derived from cyclic sulfur appears in a temperature range of 170° C. or higher and lower than 250° C., a second peak derived from the cyclic sulfur appears in a temperature range of 250° C. or higher and lower than 300° C., and a peak intensity P1 of the first peak is higher than a peak intensity P2 of the second peak.

A compound represented by the Formula 1 and having an argyrodite-type crystal structure:
Li.sub.aM1.sub.xM2.sub.wPS.sub.yM3.sub.z  Formula 1
wherein M1 is at least one element of Group 2 or Group 11 of the periodic table, M2 is at least one metal element other than Li of Group 1 of the periodic table, M3 is at least one element of Group 17 of the periodic table, and wherein 4≤a≤8, 0<x<0.5, 0≤w<0.5, 3≤y≤7, and 0≤z≤2.

A compound represented by the Formula 1 and having an argyrodite-type crystal structure:
Li.sub.aM1.sub.xM2.sub.wPS.sub.yM3.sub.z  Formula 1
wherein M1 is at least one element of Group 2 or Group 11 of the periodic table, M2 is at least one metal element other than Li of Group 1 of the periodic table, M3 is at least one element of Group 17 of the periodic table, and wherein 4≤a≤8, 0<x<0.5, 0≤w<0.5, 3≤y≤7, and 0≤z≤2.

In a method for recycling all solid-state batteries, spent battery cells are dissolved in anhydrous ethanol. The resulting solution is separated into solids and supernatants which are separately processed to regenerate the solid electrolyte and the solid electrode materials. The supernatant is subjected to vacuum evaporation to precipitate an electrolyte powder, which is then annealed under flowing oxygen. The solid electrode material is regenerated by washing the solids with water, drying the washed solids, relithiating the washed solids, and annealing the relithiated solids. The resulting materials are suitable for use in fabrication of new all-solid state batteries.

In a method for recycling all solid-state batteries, spent battery cells are dissolved in anhydrous ethanol. The resulting solution is separated into solids and supernatants which are separately processed to regenerate the solid electrolyte and the solid electrode materials. The supernatant is subjected to vacuum evaporation to precipitate an electrolyte powder, which is then annealed under flowing oxygen. The solid electrode material is regenerated by washing the solids with water, drying the washed solids, relithiating the washed solids, and annealing the relithiated solids. The resulting materials are suitable for use in fabrication of new all-solid state batteries.

A positive-electrode material according to the present disclosure includes a positive-electrode active material and a cover layer 111 containing a first solid electrolyte and covering at least partially the surface of the positive-electrode active material. The positive-electrode active material and the cover layer constitute a covered active material; the positive-electrode active material has a pore volume V.sub.α, the covered active material has a pore volume V.sub.β, the positive-electrode active material has a specific surface area Sa, the covered active material has a specific surface area Sp, and at least one selected from the group consisting of 0.20<V.sub.β/V.sub.α<0.88 and 0.81<S.sub.β/S.sub.α<0.97 is satisfied.