Effects of Initial Reduction Temperature on the Microstructures and Performances of Ni/YSZ Anodes for Solid Oxide Fuel Cells

This work focuses on the effects of the reducing and sintering behavior for NiO → Ni on the microstructures and performances of conventional Ni/YSZ (YSZ: yttria-stabilized zirconia) anodes for anode-supported solid oxide fuel cells (SOFCs). A strong dependence of reducing and sintering behavior on the initial reduction temperature for NiO → Ni was demonstrated. Some identical NiO/YSZ anodes were heated from room temperature (RT) to 850° C with a heating rate of 10°C/min. and the reducing gas H₂ was provided at different temperatures, such as, RT, 600, 650 or 700°C. As a result of initial reduction temperature, the reducing process was found to obviously affect the specific surface areas (BET test), microstructures (SEM test), conductivities (conductivity test) and electrochemical performances (power output and polarization resistance) of reduced Ni/YSZ anode. A model was finally proposed to simulate the reducing and sintering mechanism and combined effects for NiO/YSZ → Ni/YSZ anodes at different initial reduction temperatures.