Enhancing sinterability and electrochemical properties of Ba(Zr0.1Ce0.7Y0.2)O3-δ proton conducting electrolyte for solid oxide fuel cells by addition of NiO

Abstract The influence of NiO on the sintering behavior and electrical properties of proton conducting Ba(Zr 0.1 Ce 0.7 Y 0.2 )O 3-δ (BZCY7) as an electrolyte supporter for solid oxide fuel cells is systematically investigated. SEM images and shrinkage curve demonstrate that the sinterability of the electrolyte pellets is dramatically improved by doping NiO as a sintering aid. The sintering aid amount and sintering temperature are optimized by analyzing the linear shrinkage, grain size and morphology for a series of sintered BZCY7 electrolyte pellets. Almost full dense electrolyte pellets are successfully formed by using 0.5–1.0 wt% NiO loading after sintering at 1400 °C for 6 h. The linear shrinkage of 0.5 wt% NiO modified BZCY7 sample is about 14.25% higher than that without NiO addition (4.81%). Energy dispersive X-ray spectroscopy analysis indicate that partial NiO might dissolve into the perovskite lattice structure and the other NiO react with BZCY7 to form BaY 2 NiO 5 secondary phase as a sintering aid. Excessive NiO is especially detrimental to the electrical properties of BZCY7 and thus lower the open circuit voltage. The electrochemical performance for a series of single cells with different concentration NiO modified BZCY7 electrolyte are measured and analyzed. The optimized composition of 0.5 wt% NiO modified BZCY7 as an electrolyte support for solid oxide fuel cell demonstrates a high electrochemical performance.