A composite material consisting of tin nanospheres anchored on and embedded in carbon nanofibers for outstanding sodium-ion storage

Benefiting from the abundant availability of sodium resources and the relative lower cost, sodium-ion batteries (SIBs) are increasingly garnering attention. However, there is a pivotal challenge in contemporary battery research, revolves around the advancement of electrode materials that are both high-performing and abundant in nature. Sn-based materials stand out as promising anodes in SIBs owing to the high theoretical capacity (847 mA h g−1) of metallic tin. Herein, a composite of Sn nanospheres anchored on and embedded in the carbon nanofibers (Sn@CNFs) has been synthesized by electrospinning and the following annealing process. After that, the Sn@CNFs was directly used as free-standing anodes for sodium-ion batteries. Remarkably, with assistance of K+ in the electrolyte, the Sn@CNFs anode sustains a capacity of 470.3 mA h g−1 over 450 cycles with a superb Coulombic efficiency (CE) of 99.71 %. Additionally, with a high cycle retention of 99.0 %, the Sn@CNFs||NVP full-cell delivers high charge and discharge capacity of 100.7 and 99.8 mA h g−1 at 0.1C after 50 cycles.