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 Pr 0.5 Ba 0.5 Mn 0.85 Co 0.15 O 3- δ (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 −2 at 800 °C and good stability for 100 h without any catalyst. In electrolysis mode, the moderate current densities of −0.42 A cm −2 for 3 vol.% H 2 O and −0.62 A cm −2 for 10 vol.% H 2 O, 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 −2 under 10 vol. % H 2 O.