Effect of Processing Parameters on the Conductivity of the Solid Oxide Anode for Fuel Cells

Good electrical conductivity is highly desirable in Ni / YSZ cermet anodes for solid oxide fuel cells (SOFCs), that operate at temperatures typically around 700 – 900 °C. The conductivity of the cell controls the polarization loss of the cell which affects the overall efficiency of the fuel cell. In the current study, the effect of processing parameters on the conductivity of the anode cermet at room temperature is studied. The cermet is prepared with two different NiO vol. % and also sintered at two different temperatures. Different sintering temperatures lead to different microstructure and overall pore volume. The dependency of the conductivity on the microstructure, pore volume, sintering temperature and also the Ni content in the cermet are analyzed. The current analysis shows that the conductivity of the anode cermet strongly depends on the overall pore volume. Increase in sintering temperature reduces the pore volume and also reduces the active electrical conduction path. Increased density also decreases the active diffusion path which eventually means that there is a reduction in electrochemically active sites. These changes directly affect the efficiency of the cell. The Ni content in the cermet also influences the conductivity. The conductivity of the cermet varies with the Ni volume present in the cermet.