COMPOSITION, MIXTURE FOR SOLID-STATE BATTERIES, SULFIDE SOLID ELECTROLYTE LAYER, ELECTRODE LAYER, AND SECONDARY BATTERY

The disclosure aims to provide a composition capable of reducing the resistance of an electrochemical device containing a sulfide solid electrolyte, a mixture for a solid-state battery, a sulfide solid electrolyte layer, an electrode layer, and a secondary battery. Provided is a composition containing: at least one fluoropolyether represented by any of the following formulas (1) to (3); and a sulfide solid electrolyte, (1) R1-O-Ra1-Rb1-O-Ra1-R1; (2) R2-Rb2-O-Ra2-Rb2-R2; and (3) R3-Rb3-O-Ra3-R3.