Ni_(1-x)Cu_x alloy-based anodes for low-temperature solid oxide fuel cells with biomass-produced gas as fuel

摘要

Ni-Cu alloy-based anodes, Ni_(1-x)Cu_x (x approx = 0, 0.05, 0.2, 0.3)-Ce_(0.8)Sm_(0.2)O_(1.9) (SDC), were developed for direct utilization of biomass-produced gas in low-temperature solid oxide fuel cells (LT-SOFCs) with thin film Ce_(0.9)Gd_(0.1)O_(1.95) electrolytes. The alloys were formed by in situ reduction of Ni_(1-x)Cu_xO_y composites synthesized using a glycine-nitrate technique. The electrolyte firms were fabricated with a co-pressing and co-firing technique. Electrochemical performance of the Ni_(1-x)Cu_x-SDC anode supported cells was investigated at 600 deg C when humidified (3 percent H_2O) biomass-produced gas (BPG) was used as the fuel and stationary air as the oxidant. With Ni-Cu alloys as anodes, carbon deposition was substantially suppressed and electrochemical performance of the cells was sustained for much longer periods of time. For example, the power export of a Ni-SDC supported cell was only 50 percent of the initial value (200 mW cm~(-2) at 0.5 V) after 20 min, while Ni_(0.8)Cu_(0.2)-SDC supported cells could maintain 90 percent of the initial power density (250 mW cm~(-2) at 0.5 V) over a period of 10 h. The improved performance of the Ni-Cu alloy-based anodes is worth considering in developing SOFCs fueled directly with dilute hydrocarbons such as gases derived from biomass.