Robust SnO2−x Nanoparticle‐Impregnated Carbon Nanofibers with Outstanding Electrochemical Performance for Advanced Sodium‐Ion Batteries

The sluggish sodium reaction kinetics, unstable Sn/Na 2 O interface, and large volume expansion are major obstacles that impede practical applications of SnO 2 ‐based electrodes for sodium‐ion batteries (SIBs). Herein, we report the crafting of homogeneously confined oxygen‐vacancy‐containing SnO 2− x nanoparticles with well‐defined void space in porous carbon nanofibers (denoted SnO 2− x /C composites) that address the issues noted above for advanced SIBs. Notably, SnO 2− x /C composites can be readily exploited as the working electrode, without need for binders and conductive additives. In contrast to past work, SnO 2− x /C composites‐based SIBs show remarkable electrochemical performance, offering high reversible capacity, ultralong cyclic stability, and excellent rate capability. A discharge capacity of 565 mAh g −1 at 1 A g −1 is retained after 2000 cycles.