Facile synthesis of yolk–shell MoO2 microspheres with excellent electrochemical performance as a Li-ion battery anode

Abstract

In this paper, a facile and template-free solvothermal method has been developed to synthesize yolk–shell MoO₂ microspheres. The as-synthesized MoO₂ microspheres are composed of both a uniform porous shell of 80 nm in thickness and a porous core constructed from primary MoO₂ nanocrystal clusters of 20 nm in size. Importantly, the unique yolk–shell MoO₂ microspheres exhibit excellent electrochemical performance. At a current density of 50 mA g⁻¹, they can deliver a high specific capacity of 955 mA h g⁻¹ in the first discharge and retain a reversible capacity of 847.5 mA h g⁻¹ after 50 cycles. Meanwhile, even at a high current density of 2000 mA g⁻¹, they also exhibit a specific capacity of 450 mA h g⁻¹. This superior electrochemical performance of the as-synthesized MoO₂ microspheres could be ascribed to their special yolk–shell structure, which could not only provide short Li-ion and electron pathways, but also accommodate large volume variation.