Electrochemical properties of different anodes for solid oxide fuel cells

Four different types of anodes were successfully fabricated by screen printing on 8YSZ tapes and tested from 850 deg C to 950 deg C with humidified hydrogen as fuel. The examined porous anodes were Ni/8YSZ and Ni/20CGO cermets, LCaTC ceramic and LCaTC/8YSZ composite. LCaTC and LCaTC/8YSZ composite were possible promising anode materials. However, these materials showed a low electronic conductivity and, as result, very low electrochemical properties. Ni/YSZ and Ni/CGO anodes showed a high electrochemical activity. For both these anodes the cell resistance decreased with increasing pH 20 in hydrogen. Diffusional limitations were observed only for the cell with Ni/20CGO anode, probably caused by oxygen diffusion in the pores of the composite cathode, indicating that its microstructure has to be optimized in order to improve electrochemical performance.