Rationalizing the effect of surface electronic structure on oxygen electrocatalyst for high performance lithium-oxygen battery

Abstract

Lithium-oxygen (Li-O2) batteries show ultrahigh energy density compared with traditional Li-ion batteries. However, the high overpotential and the short cycle life need to be addressed before the practical application of this promising system. In this work, cerium doped cobalt nickel oxide Co2NiO4 (CCNO) is successfully prepared and studied as a high-performance catalyst for Li-O2 cells. The introduction of cerium contributes to form a large number of active sites on the catalyst surface and promotes the kinetics of oxygen redox reactions due to the modified electronic structure on the surface of CCNO nanowire array. Furthermore, the typical three-dimensional (3D) open architecture of CCNO promotes the mass transfer and thus further accelerates the electrochemical reactions. As expected, the cell based on CCNO electrode shows excellent electrochemical performance, including high discharge capacity of 9421.7 mA h g − 1 with a low overpotential of 0.59 V at a current density of 500 mA g − 1 and a long-term cycle life of more than 170 cycles. All these results clearly illustrate that cerium doping strategy provides new insights into the design of electrocatalysts for high-performance metal-air batteries.