Porous cubes constructed by cobalt oxide nanocrystals with graphene sheet coatings for enhanced lithium storage properties

Abstract

In this manuscript, graphene-encapsulated porous cobalt oxide cubes (Co₃O₄@G) are fabricated through a facile precipitation reaction with subsequent calcination and a self-assembly process. The synthesized porous Co₃O₄ cubes anchored in the conductive graphene network can realize superior electrical conductivity, withstand volume variation upon prolonged cycling and shorten the diffusion path of lithium ions. When evaluated as anode materials, the Co₃O₄@G electrode shows excellent electrochemical properties in terms of both stable cycling performance and good rate capabilities. For example, a reversible discharge capacity of 980 mA h g⁻¹ is delivered after 80 cycles at a current density of 200 mA g⁻¹. Introducing a conductive graphene network to modify other metal oxides with poor electric conductivity and large volume excursions is of great interest in the development of lithium ion battery technologies.