Defect-rich SnS2-xSex nanodots embedded in N-doped carbon nanofibers facilitating fast and stable sodium-ion storage

Sodium-ion batteries (SIBs) show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries (LIBs). However, the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion (Na + ) radius hinder the practical application of SIBs. Here, we successfully prepared SnS 2− x Se x nanodots embedded within N-doped carbon nanofibers (CNF) for use as electrode materials of SIBs. The introduction Se provided abundant anionic defect sites for sodium-ion storage and enlarged the interlayer spacing of SnS 2 . In addition, the ultrafine nanodot structure reduces the volume expansion of SnS 2− x Se x and shortens the ion transport path. As an anode of SIBs, SnS 2− x Se x /CNF demonstrates remarkable reversible capacity (719 mAh g −1 at 0.5 A g −1 ), along with rapid charging ability (completing a charge in just 127 s). Meanwhile, the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg −1 at a high-power output of 5526 W kg −1 . This study presents an effective strategy for fabricating high-performance sulphide-based anode materials for SIBs, offering broad prospects for application.