Spinel NiCo2S4 as Excellent Bi-Functional Cathode Catalysts for Rechargeable Li-O2 Batteries

Abstract

Developing bi-functional catalyst is an effective way to improve the kinetics of oxygen electrochemistry and promote the performance of Li-O2 batteries. In this study, spinel NiCo2S4 with urchin-like and yolk-shell morphologies were successfully synthesized and evaluated as cathode catalysts for rechargeable Li-O2 batteries. The results demonstrate both NiCo2S4 materials are catalytically active toward ORR/OER, but the urchin-like NiCo2S4 performs better with faster kinetics, higher capacity, lower polarization and longer cycle life. Moreover, cycling performance of the Li-O2 batteries with urchin-like NiCo2S4 is evidently better than the reported data in literatures for the batteries with many other transition metal sulfides.