Rational design of a hierarchical N-doped graphene-supported catalyst for highly energy-efficient lithium–oxygen batteries

Abstract

Integrating carbonaceous materials with metal oxides to construct a robust 3D network is a powerful yet challenging option to improve the performance of Li–O₂ batteries. Herein, a facile bottom-up method was developed to prepare N-doped graphene strengthened by cross-linked uniform cobalt oxide nanoparticles. This distinctive structure provided essential properties for oxygen cathodes, including an intrinsically high catalytic activity, inherently open active sites, large accessible surface areas, and a continuous porous nature for the accommodation of discharge products. Consequently, it was observed that this interesting nanostructure manifested a satisfying oxidation activity towards Li₂CO₃ and LiOH within the stability window of the electrolyte, which outperformed the commercial Ru/C (5%) catalyst. Also, cell measurements revealed that a superior capacity and comparable cycling performance were achieved with the discussed complex electrode in pure O₂, N₂, CO₂ and even ambient air. As such, the present study rationalized the great potential of the fabricated N-enriched graphene-dispersed catalyst in the transition from Li–O₂ to Li–air batteries.