Solid electrolyte, electrode mixture, solid electrolyte layer, and all-solid-state battery

A solid electrolyte which contains 100 ppm to 1000 ppm by mass of aluminum and has lithium ion conductivity. The aluminum is preferably derived from an aluminum oxide. The solid electrolyte is preferably a sulfide solid electrolyte containing elemental lithium, elemental phosphorus, and elemental sulfur. The solid electrolyte is preferably a substance having an argyrodite crystal structure. The solid electrolyte also preferably has a lithium ion conductivity of 4.0 mS/cm or more. 一种固体电解质，其以质量基准计含有100ppm～1000ppm的铝，具有锂离子传导性。铝适宜来源于铝氧化物。固体电解质还适宜为含有锂元素、磷元素及硫元素的硫化物固体电解质。固体电解质还适宜为具有硫银锗矿型晶体结构的物质。固体电解质还适宜锂离子传导率为4.0mS/cm以上。