For practical utilization of proton-conducting ceramic fuel cells and electrolyzers, it is essential to lower the sintering temperature and processing time of BaZrO3-based proton conductors. We investigated the effect of sintering temperature and time on the structural and electrochemical properties of dense BaZr0.8Y0.2O3 (BZY) prepared by a solid-state reactive sintering process, using NiO as a sintering aid. The sintered BZY prepared from the micronized precursor powder exhibited a density higher than 93%, and an average grain size in the range of 0.6 to 1.4 μm. The orthorhombic BaY2NiO5 phase was also observed in the sintered BZY from the combined conventional and synchrotron X-ray diffraction measurements. Electrochemical impedance spectroscopy showed that the total proton conductivities of BZY can be modulated by sintering temperature in a wet reducing atmosphere. The maximum total ion transport number achieved was 0.89 at 600 °C, and the maximum power density of the symmetric BZY electrolyte supported cell with Pt electrodes was 5.24 mWcm-2 at 900 °C.
Funding: This work was conducted under the framework of the Research and Development Program of the Korea Institute of Energy Research (KIER) (B8-2461-02). This work was also supported by the Soonchunhyang University Research Fund. Dr. Laura Navarrete (Universidad Polit\u00e9cnica de Valencia, Spain) and Jong Hyun Park (Chungnam National University) are gratefully acknowledged for the EIS measurements and analysis.
