Graphene-induced growth of single crystalline Sb2MoO6 sheets and their sodium storage performance

Abstract

A single crystalline molybdenum antimony oxide (Sb₂MoO₆) sheet/reduced graphene oxide (RGO) composite is reported for the first time, for use as an anode for a sodium ion battery with excellent cyclability and rate performance. The addition of graphene oxides in the hydrothermal synthesis can not only induce the tabular growth of Sb₂MoO₆ single crystals but also serves as a conductive network in the electrochemical reactions. The Sb₂MoO₆/RGO composite exhibits a capacity of 430 mA h g⁻¹ at 0.05 A g⁻¹ and maintains 270 mA h g⁻¹ at a high current density of 4 A g⁻¹. A capacity retention of 93.2% can be acquired after 220 cycles at 0.2 A g⁻¹. In situ X-ray diffraction, ex situ transmission electron microscopy and X-ray photoelectron spectroscopy reveal a conversion reaction in the initial cycle of the Sb₂MoO₆/RGO composite. Thus, the reversible capacity is mainly imparted by the alloying/dealloying reactions of the antimony element, while amorphous molybdenum oxide (MoO_x) and sodium oxide (Na₂O) composites serve as the buffer matrix.