DIPHOSPHORUS PENTASULFIDE COMPOSITION FOR SULFIDE-BASED INORGANIC SOLID ELECTROLYTE MATERIAL

Provided is a diphosphorus pentasulfide composition for a sulfide-based inorganic solid electrolyte material, in which a molar ratio (S/P) of a content of sulfur (S) to a content of phosphorus (P) is 2.40 or higher and 2.49 or lower. In the diphosphorus pentasulfide composition for a sulfide-based inorganic solid electrolyte material, in a DSC curve of the diphosphorus pentasulfide composition obtained by measurement using a differential scanning calorimeter under conditions of a start temperature of 25° C., a measured temperature range of 30° C. to 350° C., a temperature increase rate of 5° C./min, and an argon atmosphere with a flow rate of 100 ml per minute, an endothermic peak is shown in a temperature range of 280° C. or higher and 300° C. or lower, and a half-width of the endothermic peak is 4.1° C. or higher.