A simple, low-cost and scalable synthesis of SbSn@C composite for stable sodium-ion batteries

With low redox potential, natural abundance and cost-effective of sodium resources, sodium-ion batteries (SIBs) are considered as a promising alternative for the currently dominant energy storage devices, i.e., lithium-ion batteries. However, developing suitable anode materials is still a challenge for the practical applications of SIBs. Alloy anodes have high specific capacity and low operating voltage, but the inherent volume expansion results in rapid capacity decay and poor cycling stability. Herein, focus on this issue, a novel carbon-coated alloy composite (SbSn@C) was synthesized by the solid-phase reduction of chloride method. Surface morphology analysis confirms that the SbSn@C composite exhibits a porous structure with a carbon layer of 20–30 nm, which can accommodate volume expansion. Furthermore, the synthesized SbSn@C composite exhibits impressive electrochemical performance with a good reversible capacity (450.5 mAh g⁻¹ after 100 cycles, 90% capacity retention). As expected, such synthesis strategy provides a basis for the development of cost-effective and environmentally friendly sodium-ion batteries.