Layered barium cobaltite structure materials containing perovskite and CdI2-based layers for reversible solid oxide cells with exceptionally high performance

Abstract

To improve the sluggish kinetics of oxygen electrode reactions in reversible solid oxide cells (RSOCs), a novel layered structure Nd0.1Ca0.1Ba1.8Co9O14 (NCBCO) having alternating perovskite and CdI2-based layers is introduced in this field for the first time as a highly active and durable catalyst. Maximum power densities of NCBCO with zirconia-based cells are high, reaching 2.6 W·cm−2 at 800 °C in solid oxide fuel cell (SOFC) mode. Under a solid oxide electrolysis cell (SOEC) mode, the zirconia-based cell with NCBCO achieves an outstanding current density of − 4.36 A·cm−2 at 800 °C with an applied voltage of 1.6 V, surpassing many results of the reported oxygen evolution reaction catalysts with the high activities. Furthermore, RSOCs with NCBCO presents no degradation over entire 400 h in SOFC and SOEC modes. Such outstanding electrocatalytic performances of NCBCO for oxygen electrode reactions might be attributed to its high oxygen vacancy content with a high electrical conductivity. This is confirmed by X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of oxygen, and electron paramagnetic resonance measurements. These results validate that the layered structure NCBCO can be a potential oxygen electrode material for RSOCs.