SULFIDE SOLID ELECTROLYTE AND METHOD OF PRODUCING THE SAME

Provided are a sulfide solid electrolyte having a small particle size and a low specific surface area; an electrode composite material, a slurry and a battery in each of which the sulfide solid electrolyte is used; and a method of producing the sulfide solid electrolyte. The sulfide solid electrolyte contains lithium (Li), phosphorus (P) and sulfur (S) elements and has: a median diameter Dof 0.10 μm or more and 2.0 μm or less; and a value of the formula: (A×B)/C, wherein A represents a BET specific surface area (m/g), B represents a true density (g/cm), and C represents a CS value (m/cm), of 1.0 or more and 2.5 or less.