Fabrication of high-performance proton-conducting electrolytes from microwave prepared ultrafine powders for solid oxide fuel cells

Abstract

The microwave sintering method is found to have advantages over the conventional thermal treatment method for preparing BaZr0.1Ce0.7Y0.2O3-δ powder. Comparing with the conventional thermal treatment, the microwave sintering method allows the solid material to be self-heated, enabling the formation of pure phase BaZr0.1Ce0.7Y0.2O3-δ powder at a relatively low temperature (900 °C) with a short dwell time of 1 h, while the same pure phase can only be formed at 1000 °C in an electric furnace. Importantly, the grain size for the microwave prepared BaZr0.1Ce0.7Y0.2O3-δ powder is much smaller than that of the conventionally thermal treated BaZr0.1Ce0.7Y0.2O3-δ powder. The small powder grain size is found to be beneficial for the densification and grain growth of the resultant electrolyte membrane during the electrolyte sintering procedure. A fuel cell fabricated using this electrolyte membrane with a conductivity of 7 × 10−3 S cm−1 delivers a power output of 791 mW cm−2 at 700 °C.