Improving catalytic activity of layered lithium transition metal oxides for oxygen electrode in metal-air batteries

Lithium transition metal oxide has superior performance for oxygen evolution reaction (OER), while its activity for catalyzing oxygen reduction reaction (ORR) is too low to meet the demand of practical applications. Herein, the NCM-based (NCM, LiN1/3Co1/3Mn1/3O2) composite materials are prepared through the two steps method. The NCM-2 (Mn2O3/(LiN1/Co1/3Mn1/3O2)-Co-3) hybrid material demonstrates excellent ORR catalytic property and high OER catalytic performance, as well as the superior stability. Besides, with NCM-2 hybrid materials as catalysts of air cathode, the Al-air battery and Zn-air battery both exhibit higher power density. Therefore, based on results of Brunauer-Emmett-Teller and O-2 temperature programmed desorption analysis, the improved catalytic performance ascribed to large specific surface area, pore structure and enhanced oxygen adsorption ability. In this work, the catalytic activity of lithium transition metal oxide has been improved, and a new method was provided to synthesize bifunctional catalysts for metal-air batteries. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.