Greatly enhancing the bifunctional oxygen catalytic activities of cobalt-based perovskites by anchoring metal sulfides

Abstract

Co-based perovskites have been considered as the promising bifunctional oxygen catalysts for zinc-air batteries (ZABs) though their catalytic activities toward oxygen reduction reaction (ORR) are still need to be improved. In this work, we adopt a facile method to anchor MnS, CoS2 with high ORR activity on SrNb0.1Co0.7Fe0.2O3-δ (SNCF) surface. The optimized perovskite hybrid (SNCF-Mn-S4) exhibits the highest bifunctional oxygen catalytic activity among most of the perovskites, and its half-wave potential (E1/2) positively shifts as high as 180 mV compared with that of SNCF. The aqueous ZAB with SNCF-Mn-S4 has the high peak power density of 129.4 mW cm−2 and excellent cycling stability during 4500 charge-discharge cycles. Moreover, the energy efficiency of ZAB with SNCF-Mn-S4 can reach as high as 82%. This can be ascribed to the high oxygen catalytic activity of SNCF-Mn-S4 and hybrid effects of oxygen catalytic reactions and ion conversion reactions caused by CoS2, CoO and Co-based perovskite. Our works provides a feasible strategy for developing the Co-based perovskites with superior bifunctional catalytic properties for the high-performance ZABs.