Composition and energy storage device

A cathode composition is provided. The cathode composition includes at least one electroactive metal, wherein the electroactive metal is at least one selected from the group consisting of titanium, vanadium, niobium, molybdenum, nickel, iron, cobalt, chromium, manganese, silver, antimony, cadmium, tin, lead and zinc; a first alkali metal halide; an electrolyte salt comprising a reaction product of a second alkali metal halide and a metal halide, wherein the electrolyte salt has a melting point of less than about 300 degrees Centigrade; and a metal chlorosulfide compound having a formula (I) M1M2p+1SnCl4+3p−2n wherein M1 is a metal selected from group IA of the periodic table, M2 is a metal selected from group IIIA of the periodic table, p is 0 or 1, and n is equal to or greater than 0.5. An article and an energy storage device comprising the cathode composition is provided. A method of forming the energy storage device is provided.