Defect regulation of heterogeneous nickel-based oxides via interfacial engineering for long-life lithium-oxygen batteries

Interface engineering is crucial strategy for the sensible design and synthesis of high-efficiency electrocatalysts. However, the study on the effect of interfacial heterogeneity on the kinetics of oxygen electrode reactions in lithium-oxygen (Li-O-2) batteries tends to be neglected, which restricts the development of excellent performance Li-O-2 batteries. Here, a cactus-like nickel-cobalt oxide and nickel oxide heterostructure (NCO@NO) was successfully prepared and used for Li-O-2 batteries as catalyst. The built-in electric field at the heterogeneous interface between NiO and NiCo2O4 can significantly enhance the interface charge transfer kinetics, and its unique cactus-like structure facilitates the exposure of abundant catalytic active sites. Due to the synergistic interaction between surface structure and heterogeneous interface, the NCO@NO based cathode exhibits a large discharge capacity of 17463.5 mA h g(-1), an improved overpotential of 0.98 V, and an excellent long-term cycle stability (the terminal discharge voltage of the NCO@NO based Li-O-2 battery shows negligible attenuation after cycling up to 500 times). (C) 2019 Elsevier Ltd. All rights reserved.