An SbO_x/reduced graphene oxide composite as a high-rate anode material for sodium-ion batteries

Antimony has attracted enormous attention as anode materials for sodium-ion batteries owing to its high theoretical gravimetric capacity (∼660 mA h g^-1). Despite the outstanding gravimetric capacity advantage, antimony suffers from unsatisfactory electrochemical performance originating from its huge volume changes during repeated sodium insertion/extraction. Herein, we synthesize an SbO_x/reduced graphene oxide (SbO_x/RGO) composite through a wet-milling approach accompanied by redox reaction between Sb and GO. When used as an anode material for sodium-ion batteries, SbO_x/RGO exhibits high rate capability and stable cycling performance. A reversible capacity of 352 mA h g^-1 was obtained even at a current density of 5 A g^-1. More than 95% capacity retention (409 mA h g^-1) was achieved after 100 cycles at a current density of 1 A g^-1. The excellent electrochemical performance is due to the Sb-O bonding between nanometer-sized SbO_x particles surface and highly conductive RGO, which can not only effectively prevent SbO_x nanoparticles from aggregation upon cycling but also promote the electrons and sodium ions transportation.