▎ 摘　　要

NOVELTY - An iron disulfide compound (I), as a cathode active material, is new. USE - The compound (I) is used as a cathode composition for preparing a solid-state battery (claimed), rechargeable batteries at high temperatures and non-rechargeable batteries at ambient temperatures, and in photovoltaic applications. ADVANTAGE - The compound (I) has improved conductivity, enhanced battery performance, improved electron transfer reaction, and improved energy density by enhancing both capacity and voltage, and is prepared by simple and cost-effective preparation process. The solid-state battery has high battery capacity and increased cyclability. DETAILED DESCRIPTION - An iron disulfide compound of formula: aFeS2(1-a)LiX (I), as a cathode active material, is new. X = F, Cl, Br or I;and a = 0.75-0.9. INDEPENDENT CLAIMS are included for the following: (1) (1) a cathode composition comprising (a) 45-55 (weight/weight)% compound (I), (b) at least one conductive carbon, and (c) at least one additive; and (2) (2) a solid-state battery comprising compound (I) or the cathode composition, an anode, and an electrolyte.