Proton-conducting fuel cells operating on hydrogen, ammonia and hydrazine at intermediate temperatures

Anode-supported proton-conducting fuel cell with BaZr_0.1Ce_0.7Y_0.2O_3-δ (BZCY) electrolyte and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF) cathode was fabricated. Peak power densities of ∼420 and 135 mW/cm² were achieved, respectively, at 700 and 450 °C for a cell with 35 μm thick electrolyte operating on hydrogen fuel. The endothermic nature of the ammonia decomposition reaction, however, resulted in cell temperature 30-65 °C lower than the furnace when operating on ammonia. Accounting the cooling effect, comparable power density was achieved for the cell operating on ammonia and hydrogen at high temperature. At reduced temperature, the cell demonstrated worse performance when operating on ammonia than on hydrogen due to the poor activity of the anode towards NH₃ catalytic decomposition. By applying on-line catalytic decomposition products of N₂H₄ as the fuel, similar cell performance to that with NH₃ fuel was also observed.