High-mass-loading Sn-based anode boosted by pseudocapacitance for long-life sodium-ion batteries

Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries in large-scale energy storage due to the abundant sodium resources and low cost. However, the practical applications are still hindered by several factors such as limited cycling life and low mass loading of the electrode. Herein, a uniform free-standing Sn-based (Sn@CFC) electrode was synthesized via a facile electrospinning method. The cross-link nitrogen-doped carbon fiber and ultrasmall metallic Sn nanoparticles together provide fast ions and electrons pathway, enabling a dominant pseudocapacitance contribution of 87.1% at a scan rate of 0.5 mV s⁻¹. The Sn@CFC electrode hence exhibits a high reversible area capacity of 1.68 mAh cm⁻² at 50 mA g⁻¹ and long cycle life of 1000 cycles at 200 mA g⁻¹ with more than 80% capacity retention. Moreover, the facile manufacturing technique yields the Sn@CFC electrode with an extremely high mass loading of 5.5 mg cm⁻² with very little sacrifice of electrochemical performances. This study provides a promising route to scalably fabricate electrodes with high area capacity and high energy density for advanced SIBs.