Fluoride-Based, Low Temperature Solid Electrolyte Fuel Cell 929290
Lanthanum fluoride electrolytes were tested to determine whether fluoride electrolytes can be used as fuel cell electrolytes at low temperatures. The planar-type fuel cell were operated in oxygen/hydrogen gases with nickel oxide/nickel as the anode and a perovskite-structure oxide (La0.6Sr0.4CoO3) as the cathode. In order to reduce the fuel cell operating temperature while maintaining the highest possible current, various thin and thick film techniques were assessed. They include e-beam evaporation and DC plasma spray methods. Fuel cells incorporating plasma-sprayed LaF3 films yielded a short-circuit current density on the order of 0.4 mA/cm2 at 450°C, and the current density under an overpotential of 0.2V showed no sign of decay over 17 hours. In the co-ionic (fluoride and oxide ion) conduction mode, the lanthanum fluoride electrolyte based fuel cells could sustain current in oxygen/hydrogen gases.