Self-Transforming Configuration Based on Atmospheric-Adaptive Materials for Solid Oxide Cells.

Solid oxide cells (SOC) with a symmetrical configuration have been focused due to the practical benefits of such configurations, such as minimized compatibility issues, a simple fabrication process and reduced cost compared to SOCs with the asymmetrical configuration. However, the performance of SOCs using a single type of electrode material (symmetrical configuration) is lower than the performance of those using the dissimilar electrode materials (asymmetrical configuration). Therefore, to achieve a high-performance cell, we design a 'self-transforming cell' with the asymmetric configuration using only materials of the single type, one based on atmospheric adaptive materials. Atmospheric-adaptive perovskite PrBaMnCoO (PBMCo) was used for the so-called self-transforming cell electrodes, which changed to layered perovskite and metal in the fuel atmosphere and retained its original structure in the air atmosphere. In fuel cell mods, the self-transforming cell shows excellent electrochemical performance of 1.10 W cm at 800 °C and good stability for 100 h without any catalyst. In electrolysis mode, the moderate current densities of -0.42 A cm for 3 vol.% HO and -0.62 A cm for 10 vol.% HO, respectively, were observed at a cell voltage of 1.3 V at 800 °C. In the reversible cycling test, the transforming cell maintains the constant voltages for 30 h at +/- 0.2 A cm under 10 vol. % HO.