Effects of doping alumina on the electrical and sintering performances of yttrium-stabilized-zirconia

The effects of doping amount and particle size of alumina on the sintering behavior and electrical performance of 8mol% yttria-stabilized zirconia (YSZ) are investigated through microstructure and impedance spectroscopy analysis. Initial results show that a proper amount of Al2O3 doping can effectively improve the sintering behavior and the electrical performance of YSZ, and the optimum doping amount varies with the particle size of Al2O3. When a raw Al2O3 powder (modal particle size: 0.28μm) is used as dopant, the optimal doping amount for electrical and sintering improvement is 0.7wt.% and 3wt.%, respectively, while that with 1400°C-calcined-Al2O3 (0.45μm), 1wt.% and 4wt.%. A concept of space distribution distance of the doping particles is introduced to interpret the improvement effect. •Proper amount of Al2O3 doping can improve sintering and electrical properties of YSZ.•Particle size of doping Al2O3 powder affects the doping effects of Al2O3-doped YSZ.•Al2O3 particle distribution in YSZ determines the grain size of Al2O3-doped YSZ.•Larger mass of Al2O3 with larger particle size is needed to get optimum performance.•1wt.% Al2O3doping into YSZ electrolyte enhances the SOFC output by 20%.