Amorphous Molybdenum Sulfide Electrodes for Nonaqueous Electrochemical Cells

Abstract

A series of amorphous molybdenum sulfides, , and , have been investigated as candidate nonaqueous storage battery electrodes. The molybdenum sulfides were prepared by a low temperature nonaqueous precipitation technique from molybdenum halides and hexamethyldisilathiane; classical was also prepared from ammonium tetrathiomolybdate by both thermal decomposition and acidic precipitation from an aqueous solution. Mechanically stable electrodes were fabricated by spraying a suspension of active material, an inert polymer binder, and carbon black on an aluminum foil substrate. Electrochemical performance is dependent on the stoichiometry of the molybdenum sulfide, as well as the details of the cycling regime. Amorphous molybdenum trisulfide shows the highest energy density and longest cycle life of the three compounds. Four equivalents are discharged in the first cycle; three equivalents can be recharged and cycled at an average voltage of about 1.9V in excess of 200 cycles to 50% of initial recharge capacity.