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

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.