Eugene Vamos

Advances in direct oxidation methanol fuel cells

Fuel cells that can operate directly on fuels such as methanol are attractive for low to medium power application in view of their low weight and volume relative to other power sources. A liquid feed direct methanol fuel cell has been developed based on a proton-exchange membrane electrolyte and Pt/Ru and Pt-catalyzed fuel and air/O2 electrodes, respectively. The cell has been shown to deliver significant power outputs at temperatures of 60 to 90 °C. The cell voltage is near 0.5 V at 300 mA/cm2 current density and an operating temperature of 90 °C. A deterrent to performance appears to be methanol crossover through the membrane to the oxygen electrode. Further improvements in performance appear possible by minimizing the methanol crossover rate.

Status of the development of rechargeable lithium cells

Abstract The progress in the development of the ambient temperature lithium-titanium disulfide rechargeable cell under development at the Jet Propulsion Laboratory is described in this paper. Originally aimed at achieving a specific energy of 100 Wh/kg, ‘AA’ cells have demonstrated 125 Wh/kg at the C /3 discharge rate. The results of evaluating cell design parameters are discussed and cycling test data are also included in the paper. Safety-tests results at various overcharge and overdischarge conditions and rates proved to be uneventful. The test results of cell with built-in overcharge mechanism proved the concept was feasible. Replacing the lithium foil electrode with a Li x C resulted in a capacity at 1 mA/cm 2 of 200 mAh/g and 235 mAh/g at 0.167 mA.