Tailored Combination of Low Dimensional Catalysts for Efficient Oxygen Reduction and Evolution in Li-O-2 Batteries

Abstract

The development of efficient bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key issue pertaining high performance Li-O-2 batteries. Here, we propose a heterogeneous electrocatalyst consisting of LaMnO3 nanofibers (NFs) functionalized with RuO2 nanoparticles (NPs) and non-oxidized graphene nanoflakes (GNFs). The Li-O-2 cell employing the tailored catalysts delivers an excellent electrochemical performance, affording significantly reduced discharge/charge voltage gaps (1.0V at 400mAg(-1)), and superior cyclability for over 320cycles. The outstanding performance arises from (1)the networked LaMnO3 NFs providing ORR/OER sites without severe aggregation, (2)the synergistic coupling of RuO2 NPs for further improving the OER activity and the electrical conductivity on the surface of the LaMnO3 NFs, and (3)the use of GNFs providing a fast electronic pathway as well as improved ORR kinetics.