Preparation, Optimization And Hydrogen Oxidation Kinetics Of Solid Oxide Fuel Cell Anodes

Doped LaGaO3 perovskites exhibit high oxygen ion conductivity and good stability, which is a kind of excellent potential electrolytes for intermediate temperature solid oxide fuel cells(ITSOFC). The history of study on ITSOFCs based on doped LaGaO3 electrolyte is not long, it is essential to develop promising anodes compatible with the electrolyte. In this study, high performance Ni-doped LaGaO3 composite anodes were prepared and optimized, and multiple techniques were applied to study the kinetics of hydrogen oxidation over the electrodes.Various Ni-doped LaGaO3 composite anodes were prepared. Single cells were constructed using Ni-doped LaGaO3 as anodes, series Sr, Mg, and Co doped lanthanum gallate as electrolytes, and Sm0.5Sr0.5CoO3(SSC)- La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)as cathodes. The electrochemical characteristics of the anodes were studied using polarization and AC impedance spectrometry, and the power outputs of corresponding cells were measured. The results demonstrated that the performance of the Ni-doped LaGaO3 composite anodes depended strongly on the sintering temperature of the electrodes, and the optimum sintering temperature was about 1473K. The amount as well as the composition of the doped LaGaO3 added into the anode had strong effect on the anode performance. For the La0.8Sr0.2Ga0.8Mg0.2-xCoxO3(LSGMC, x<0.085) additives studied, the performance of the composite anode increased with increasing amount of cobalt in LSGMC. Further, the optimum concentration of LSGMC in Ni-LSGMC composite anodes was about 25wt %. Electrolytes supporting the anodes also played an important role in determining the activity of the anodes. Among the La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM9182), LSGMC5, and La0.8Sr0.2Ga0.8Mg0.115Co0.085O3 (LSGMC8.5) electrolytes studied, the activity of anodes increased with increasing amount of cobalt in the electrolytes. Ni-doped LaGaO3 composite anodes were effective for the oxidation of both hydrogen and methane, however, the powder density using methane as a fuel was lower than that using hydrogen as a fuel.High performance Ni-Fe-LaGaO3 composite anodes were developed for the first...