Degradation mechanism of Ni-based anode in low concentrations of dry methane

摘要

Degradation mechanism of Ni_(0.5)Cu_(0.5)-Gd_(0.2)Ce_(0.8)O_(1.9) (CGO) bimetallic anode in low concentrations of dry methane is studied with a (La_(0.75)Sr_(0.25))_(0.95)Mn0_(3-Leakage tests suggested that as-prepared cells are well-sealed by glass ring at elevated temperatures. OCV of as-prepared cell in each concentration of CH4 is over 1.2 V, indicating that the ScSZ electrolyte film prepared by a dual drying pressing method is dense enough. It is found that rapid degradation phenomenon easily occurred at relatively high current density in 7.4 and 14.8% of dry methane in the performance test. XRD and EIS analyses indicated that the degradation of the Ni_(0.5)Cuo.5-CGO anode at high current density could be mainly attributed to the re-oxidation of Ni. GC results showed that the re-oxidation of Ni always occurred at a relatively high p(H_2O), which always appeared at a relatively high current density. The degraded cell is successfully recovered by burning the anode with O_2 and re-reducing with H_2.