High performance non spinel cobalt manganese mixed oxide based bifunctional electrocatalysts for rechargeable zinc air batteries
Abstract Development of efficient bifunctional electrocatalysts from earth abundant elements, simultaneously active for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains to be a grand challenge for electrocatalysis. Herein we firstly synthesized a new type of bifunctional catalyst (NCNT/CoxMn1 xO) consisting of non spinel cobalt manganese oxide supported on N doped carbon nanotubes through a simple non surfactant assistant hydrothermal method. This hybrid catalyst exhibits much higher OER activity than that of IrO2, and comparable ORR activity to Pt/C with identical onset potential (0.96 V) in alkaline media. Furthermore, the NCNT/CoxMn1 xO catalyst was studied as a cathode in both primary and rechargeable zinc air batteries demonstrating similar performance to commercial Pt/C or (Pt/C+IrO2) respectively. Primary zinc air battery tests show a gravimetric energy density of 695 W h kg Zn 1 and the rechargeable battery exhibits a high round trip efficiency evidenced by a low discharge charge voltage gap (0.57 V) at a current density of 7 mA cm 2.