C/Sn/RGO Nanocomposites as Higher Initial Coulombic Efficiency Anode for Sodium-Ion Batteries

Theoretically, metal Sn owns higher initial coulombic efficiency than SnO₂ in the sodium-ion batteries (SIBs). Metal Sn is commonly obtained by the thermal reduction of SnO₂ at present. However, the uncontrollable growth of metal Sn particles during the reduction progress is a key challenge. In this work, a composite material of refined metal Sn particles (particle size about 20∼200 nm) and carbon buffer medium has been prepared by a novel method, which is simple thermal reduction adopted after the treatment of SnO₂/RGO in the pitch kerosene solution. The results show that this method overcomes the uncontrollable growth of metal Sn particles. Electrochemical tests show that C/Sn/RGO possesses a higher initial reversible capacity of 476.2 mAh g⁻¹, and a higher initial coulombic efficiency of 70.3%. This method would have wider applications for the attractive properties of Na-ion batteries in the future.