Synthesis and electrochemical properties of Ba1-xCaxCe0.9Y0.1O3, 0 < x< 0.1 ceramic proton conducting electrolyte

Ceramic proton conducing BaCe0.9Y0.1O3 (BCY) and BCY-based (BCY doped by the fourth cation) are considered as promising electrolytes for construction of solid oxide fuel cells operating in the intermediate temperature range (500-700 °C) and as electrolytes for construction of solid oxide electrolysers in the power to gas conversion system. These systems allowed to store electrical energy in chemical form of fuels (H2, CH4 or CH3OH). The main drawback of this group of electrolytes is limited stability in CO2 / H2O containing gas atmosphere. The partial replacement of barium by calcium in BCY leads to improvement of the electrolyte chemical stability and changes in its other physicochemical properties. The aim of this study is to summarize the impact of physicochemical properties of Ba1-xCaxCe0.9Y0.1O3, 0 < x< 0.1 (BCCY) on the performance of SOFC. Several mixed oxides of BCCY were synthesized in the form of powders then ceramic electrolytes were prepared by different methods. The stability of obtained BCCY samples and performance of BCCY electrolyte containing fuel cells are described. Behaviour of the electrochemical interface La0.6Sr0.4Co0.8Fe0.2O3-d|BCY under polarization by negative potential from -0.05 to -0.5 V typical for operation in solid oxide fuel cell mode is presented in Fig.1a whereas under polarization from 0.05 to 0.5 typical for operation in solid oxide fuel electrolyser mode in Fig. 1b. Fig. 1. Stability of current at 700 °C at La0.6Sr0.4Co0.8Fe0.2O3-d | BCY interface under negative (a) and positive (b) polarizations Acknowledgements: The European Union Erasmus+ programme (project number: 2017-1-PL01- KA103-035642) is acknowledged for providing scholarship (financial support) for the research/mobility/training. Some of the measurements were performed using scientific equipment belonging to the laboratories of the AGH-UST Energy Centre, Krakow, Poland.