Regulating sodium storage sites in carbon materials via fluorine doping for sodium-ion batteries

Carbon materials are promising candidates as anodes for sodium-ion batteries (SIBs). However, their practical application is still hindered by sluggish Na⁺ diffusion kinetics and substantial volume changes during sodiation/desodiation, which limit specific capacity and long-term cycling stability. Herein, we design fluorine-doped carbon nanorods (FCNs) with rich-edge defects to enhance sodium storage performance. F-doping induces more edge defects in carbon layers, which provide optimized active sites to enhance Na⁺ adsorption capability and alleviate volume expansion during cycling. Consequently, the FCNs deliver a sodium storage capacity of 331 mAh g^-1 at 0.1 A g^-1 and exhibit remarkable long-term cycling stability (122 mAh g^-1 after 10 000 cycles at 2 A g^-1) with a lower capacity decay rate of only 0.0035% per cycle. This work provides an effective strategy for developing high-performance F-doped carbon materials and underscores their potential for advanced sodium storage applications.