Electrochemical Properties of Solid Oxide Fuel Cell with Sm-Doped Ceria Electrolyte and Cermet Electrodes

Cermet electrodes for Sm-doped ceria electrolyte (SDC) with a composition Ce0.8Sm0.2O1.9 were prepared by freeze drying of the SDC-H2PtCl6-Cu(NO3)2 suspension (cathode) and the SDC-Ni(NO3)2-SnO2 suspension (anode). The freeze-dried powders decomposed at 873 K and were sintered at 1323-1573 K in air to investigate phase compatibility, microstructures and electrical conductivity. The dominant factors for the terminal voltage drop of the present fuel cell were the resistance of solid electrolyte and the overpotentials at both electrodes. Addition of CuO to SDC-Pt cathode and addition of SnO2 to SDC-Ni anode reduced the overpotentials at the electrodes and increased the terminal voltage and power density of the cell with SDC electrolyte (500 μm thickness) using a 97 vol% H2-3 vol% H2O fuel. The highest power density was 183 mW/cm2 at 1073 K.