Hierarchical NiCo₂O₄ nanosheets on carbon nanofiber films for high energy density and long-life Li-O₂ batteries

Abstract

Designing oxygen cathodes with both high energy density and excellent cycling stability is a great challenge in the development of lithium-oxygen (Li-O₂) batteries for energy storage systems. Herein, we design a novel structure of hierarchical NiCo₂O₄ nanosheets on porous carbon nanofiber films (denoted as NiCo₂O₄@CNFs) as an oxygen cathode for lithium-oxygen batteries. The NiCo₂O₄@CNFs cathode delivers a high specific discharge capacity of 4179 mA h g⁻¹, a high energy density of 2110 W h kg⁻¹ and superior cycling stability over 350 cycles. The excellent electrochemical performance of the NiCo₂O₄@CNFs cathode can be attributed to the rational design and engineering of catalysts and porous conductive electrodes. These results indicate that the NiCo₂O₄@CNFs electrode is a promising candidate for high energy density and long-life Li-O₂ batteries. Additionally, the rational design of the hierarchical catalyst constructed low-dimensional nanostructure and the lightweight porous carbon nanofiber electrode can be also used for other metal-oxygen batteries, such as zinc-oxygen (Zn-O₂) batteries, aluminum-oxygen (Al-O₂) batteries, and sodium-oxygen (Na-O₂) batteries.