Tin sulfide nanoparticles embedded in sulfur and nitrogen dual-doped mesoporous carbon fibers as high-performance anodes with battery-capacitive sodium storage

Batteries based on sodium-ion chemistry are promising alternatives to current-generation lithium-ion ones, owing to the abundant sodium sources. The larger radius of Na+ than Li+, however, has been limiting the adaptability of many electrode materials. On one hand, the insertion of Na+ harshly requires suitable layer spacing. On the other hand, the sodiation/desodiation may cause more severe volume changes. Herein, nanosized tin sulfide embedded in sulfur and nitrogen co-doped porous carbon fibers (SnS@SNCF) were designed and synthesized from a sulfur bearing electrospinning solution. This approach promises the structural stability of SnS upon cycling to ensure high capacities. Meanwhile, it introduces sulfur doping, pores and partially graphitized edges to the carbon fibers, which can contribute to fast capacitive sodium storage. An optimized SnS@SNCF electrode shows high specific capacity of 630 mA h g(-1) at 0.1 A g(-1), good rate capability and superior cyclic stability in half-cell. It also shows potential in SnS@SNCF//Na3V2(PO4)(3) full cells.