Cu-Ni cermet anodes for direct oxidation of methane in solid-oxide fuel cells

The use of Cu-Ni alloys as anodes for the direct oxidation of methane in solid-oxide fuel cells (SOFC) at 1073 K was examined. Ceramic-metal (cermet) composites with alloy compositions of 9, 10, 20, 50 and 100% Ni were exposed to dry CH4 at 1073 K for 1.5 h to demonstrate that carbon formation is greatly suppressed on the Cu-Ni alloys compared to that of pure Ni. Increased reduction temperatures also reduced carbon formation on the alloys. The performance of a fuel cell made with a Cu(80%)-Ni(20%) cermet was tested in dry CH4 for 500 h and showed a significant increase in power density with time. Impedance spectra of similar fuel cells suggest that small carbon deposits are formed with time and that the increase in performance is due to enhanced electronic conductivity in the anode. The implications of using metal alloys for SOFC applications are discussed. 12 refs.