Composite of few-layer MoO3 nanosheets with graphene as a high performance anode for sodium-ion batteries

Identification of an appropriate anode material is one of the major challenges for rechargeable Na-ion batteries. Layered MoO3 is a potential alternative as it can reversibly store large amounts of sodium. However, MoO3 is a poor electronic conductor and undergoes large volume changes during repeated cycling. Ultrathin nanosheets of 1-3 bilayers of MoO3 are synthesized starting from the oxidation of few-layer MoS2 nanosheets. The MoO3 nanosheets are subsequently chemically tagged with optimum amounts of rGO leading to the formation of a 3D MoO3-rGO composite. The MoO3-rGO composite exhibits remarkable electrochemical stability, cyclability and high rate capability over a wide range of operating currents (0.05-1 C). This simple and novel material design strategy of MoO3-rGO provides the most optimum condition for buffering the volume changes during repeated cycling and provides facile pathways for Na-ion and electron transport in MoO3.