Performance enhanced of NiCe0.8Sm0.2O1.9 hydrogen electrode for reversible solid oxide cells with cadmium substitution

Ni 1-x Cd x O-SDC composite materials are prepared and investigated as the hydrogen electrodes for reversible solid oxide cell (RSOC). XRD, SEM, XPS and Raman techniques have been used to characterize structural properties, textural and mobility of adsorbed oxygen and lattice oxygen. After reduction, Cd is incorporated into the lattice of Ni and formed Ni Cd alloy. The reduced Ni 0.9 Cd 0.1 O-SDC possesses the most oxygen vacancies , resulting in the highest catalytic activity for the electrochemical oxidation of H 2 and the electrolysis of H 2 O. The electrochemical oxidation process of H 2 on the hydrogen electrode in solid oxide fuel cell (SOFC) mode is investigated with a symmetric cell under various H 2 partial pressures. The surface diffusion of adsorbed H atom on the reduced Ni 1-x Cd x O-SDC composite hydrogen electrodes is the rate-determining step (RDS) for H 2 electrochemical oxidation reaction and the reduced Ni 0.9 Cd 0.1 O-SDC shows the highest electrochemical oxidation rates. The maximum power densities ( P max ) of the cells with reduced Ni 0.9 Cd 0.1 O-SDC as hydrogen electrode is 796.2 mW cm −2 when using H 2 as the fuel at 700 °C. Furthermore, in solid oxide electrolysis cell (SOEC) mode, the cell with reduced Ni 0.9 Cd 0.1 O-SDC as hydrogen electrode exhibits the best electrolysis performance under various H 2 O concentrations and the current densities remain stable during the test at different voltages for a total period of 10 h under 47%H 2 O + 53%H 2 O atmosphere at 700 °C.