MoS₃ Thin Film Cathodes Prepared by Chemical Vapor Deposition

Thin films of have been prepared by chemical vapor deposition from molybdenum hexafluoride and hexamethyldisilthiane (HMDST). Continuous, adherent films were obtained at deposition temperatures in the range of 150° to 400°C on aluminum, nickel, silica, and alumina substrates. Infrared analyses indicate that deposition temperatures between 200° and 250°C produce the purest films. Growth rates in this temperature range are controlled by the reactant flow rates, and averaged 1000Å/min in this study. Four point resistivity measurements showed a minimum in film resistance (90 kΩ‐cm) at a deposition temperature of 230°C. The films were studied electrochemically in nonaqueous, secondary lithium cells. The best electrochemical performance was achieved on films deposited in the range of 210°C to 240°C, which corresponded to those films analytically determined to be . Four equivalents were discharged and three equivalents could be reversibly cycled at an average discharge voltage of 1.9V vs. lithium. Substantial capacity (≈2 equivalents) was maintained after 100 deep cycles (down to 1.0V vs. lithium) at a rate of 0.2 mA/cm².