Rapid degradation phenomenon of NiCu-Ce_(0.8)Gd_(0.2)O_(1.9) anode at high p(H_2O) in different concentrations of dry methane

摘要

Degradation phenomena of Ni_(0.5)Cu_(0.5)-CGO (Ce_(0.8)Gd_(0.2)O_(1.9)) bimetallic anode in different concentrations of dry methane were studied in LSM ((La_(0.75)Sr_(0.25))_(0.95)MnO_(3-δ))-CGO cathode supported SOFCs. According to XRD, SEM and EIS analyses, the degradation of the Ni_(0.5)Cu_(0.5)-CGO bimetallic anode could be mainly attributed to re-oxidation of Ni by H_2O and/or by rapid sintering of Ni due to a high p(H_2O) appeared at a high current density. Furthermore, it is found that the degradation of anode resulted by the re-oxidation of Ni and/or by rapid sintering of Ni in the as-prepared cells generally occurred when the partial pressure ratio of the produced H_2O and CH_4 at the outlet of anode increased above a threshold value in different concentrations of dry methane.