Measurement of oxygen reduction/evolution kinetics enhanced (La,Sr)CoO3/(La,Sr)2CoO4 hetero-structure oxygen electrode in operating temperature for SOCs

Abstract To make full use of the advantages of solid oxide cells (SOCs) under actual operating conditions, hetero-structured La 0.6 Sr 0.4 CoO 3-δ /LaSrCoO 4±δ (LSC 113/214 ) thin film electrodes are prepared and investigated by a novel high temperature micro-probe electrochemical test platform for SOCs. The results show that the surface exchange coefficient (k q ) of LSC 113/214 thin films is 3–10 times higher than that of single phase LSC 113 in 773–1123 K. ToF-SIMS and XPS characterizations show that LSC 113/214 hetero-interface leads to Sr enrichment at interfacial region and stabilizes it against detrimental Sr segregation. This hetero-interface further induces increased number of active oxygen vacancies and leads to accelerated oxygen exchange kinetics by raising O 2p center closer to Fermi level. This work provides significantly enhanced ORR/OER activity of hetero-structured LSC 113/214 oxygen electrode at operation conditions and brings substantial technical benefits for the SOC systems.