Abstract: A secondary lithium-sulfur electrochemical cell is provided comprising: (a) an anode comprising lithium; (b) a cathode comprising an electroactive sulfur-containing material; and (c) a non-aqueous electrolyte interposed between the anode and the cathode, wherein the electrolyte comprises: (i) one or more lithium salts; (ii) one or more non-aqueous solvents; and (iii) a cycle life enhancing amount of water; wherein the cycle life enhancing amount of water is greater than 3000 ppm by weight of the electrolyte. Such cells have a long cycle life.

Abstract: The present invention pertains to methods of forming solid composite cathodes with cathode active layers which comprise an electroactive sulfur-containing material and an electrically conductive material, wherein the electroactive sulfur-containing material is heated to a temperature above its melting point to form a melt layer and then is resolidified to form a cathode active layer having redistributed electroactive sulfur-containing material of high volumetric density and improved adhesion and cohesion. The present invention also pertains to methods of forming electric current producing cells comprising such solid composite cathodes and having a high electrochemical utilization and to solid composite cathodes and electric current producing cells formed using such methods.