N-doped Sb₂SnO₅@C as advanced anode material for sodium-ion batteries

Sodium-ion battery is evolving into a desirable alternative technology to lithium-ion batteries, thanks to its wide material distribution and low cost. Tin-antimony oxide is gaining research interest as a sodium-ion battery anode material owing to its ideal theoretical specific capacity, environment friendly, and low cost. However, because of the inner nature of poor electrical conductivity of oxides and slow ionic diffusion kinetic, the electrochemical performance of tin-antimony oxides (SSO) differs significantly from the theoretical value of merit. In this paper, we demonstrated N-doping porous carbon fibers encapsulated Sn/Sb@Sb₂SnO₅ composite (Sn/Sb@Sb₂SnO₅@PCFs-N) material. Through the use of a simple electrostatic spinning technique, the Sn and Sb nanocrystalline were in situ generated around the SSOs in a specific way, and the N-doping in the fabricated porous carbon fibers can modulate the charge transport in the fabricated composite. The unique structure can successfully increase the electrical conductivity and the specific capacity of the fabricated composite. Using as anode for Na⁺ ions storage, the fabricated composite delivers high specific capacity and good cycling stability and rate capability, showing a high capacity of 450 mAhg⁻¹ at 50 mAg⁻¹ current density even after 100 cycles. The better rate capability can be sustained even when the current raised up to 500 mA g⁻¹. This current work can offer a perspective on the effect of phases modified and doping on the functionality of materials for the next-generation high-specific energy sodium-ion battery.