A sulfide solid electrolyte that contains lithium, phosphorus, sulfur, chlorine and bromine, wherein in powder X-ray diffraction analysis using CuK rays, it has a diffraction peak A at 2=25.20.5 deg and a diffraction peak B at 2=29.70.5 deg, the diffraction peak A and the diffraction peak B satisfy the following formula (A), and a molar ratio of the chlorine to the phosphorus c (Cl/P) and a molar ratio of the bromine to the phosphorus d (Br/P) satisfies the following formula (1):
1.2<c+d<1.9(1)
0.845<S.sub.A/S.sub.B<1.200(A) where S.sub.A is an area of the diffraction peak A and S.sub.B is an area of the diffraction peak B.

A sulfide solid electrolyte that contains lithium, phosphorus, sulfur, chlorine and bromine, wherein in powder X-ray diffraction analysis using CuK rays, it has a diffraction peak A at 2=25.20.5 deg and a diffraction peak B at 2=29.70.5 deg, the diffraction peak A and the diffraction peak B satisfy the following formula (A), and a molar ratio of the chlorine to the phosphorus c (Cl/P) and a molar ratio of the bromine to the phosphorus d (Br/P) satisfies the following formula (1):
1.2<c+d<1.9(1)
0.845<S.sub.A/S.sub.B<1.200(A) where S.sub.A is an area of the diffraction peak A and S.sub.B is an area of the diffraction peak B.

A method for producing a solid electrolyte comprising feeding a solid electrolyte raw material-containing liquid comprising: a solid electrolyte raw material comprising lithium, phosphorus, sulfur and chlorine; and a solvent, to a liquid or gas medium having a temperature higher than the boiling point of the solvent, thereby evaporating the solvent and reacting the solid electrolyte raw material to precipitate a solid electrolyte having an argyrodite-type crystal structure.

A method for producing a solid electrolyte comprising feeding a solid electrolyte raw material-containing liquid comprising: a solid electrolyte raw material comprising lithium, phosphorus, sulfur and chlorine; and a solvent, to a liquid or gas medium having a temperature higher than the boiling point of the solvent, thereby evaporating the solvent and reacting the solid electrolyte raw material to precipitate a solid electrolyte having an argyrodite-type crystal structure.

The present disclosure relates to a material containing the elements Li, M, P, S and X wherein M=Si, Ge or Sn, and X=F, Cl, Br or I. The material can be used as a sulfide solid electrolyte material, notably for an all-solid-state lithium battery.

The present disclosure relates to a material containing the elements Li, M, P, S and X wherein M=Si, Ge or Sn, and X=F, Cl, Br or I. The material can be used as a sulfide solid electrolyte material, notably for an all-solid-state lithium battery.

Solid-state lithium ion electrolytes of lithium metal sulfide based composites are provided which contain an anionic framework capable of conducting lithium ions. An activation energy of the lithium metal sulfide composites is from 0.2 to 0.45 eV and conductivities are from 10.sup.4 to 3.0 mS/cm at 300K. Composites of specific formulae are provided and methods to alter the composite materials with inclusion of aliovalent ions shown. Lithium batteries containing the composite lithium ion electrolytes are also provided. Electrodes containing the lithium metal sulfide based composites and batteries with such electrodes are also provided.

Disclosed is a method for producing a sulfide-based solid electrolyte containing an alkali metal, a sulfur element, a phosphorus element and a halogen element, including performing a reaction of an alkali metal sulfide and a substance containing at least one element of a sulfur element, a phosphorus element and a halogen element in an organic solvent having an electron-withdrawing group. The method provides a sulfide-based solid electrolyte having a high ion conductivity.

An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.