In-situ formation of tin-antimony sulfide in nitrogen-sulfur Co-doped carbon nanofibers as high performance anode materials for sodium-ion batteries

As potential alternatives to lithium-ion batteries in grid energy storage application, sodium-ion batteries (SIBs) have attracted tremendous attention. Absence of high-performance anode material remains a challenge to commercialize SIBs. Herein, a SnSbSx/porous carbon nanofiber (SnSbSx/PCNF) composite with superior performance is successfully prepared via electrospinning, followed by a sulfuration treatment. The as-prepared SnSbSx/PCNF composite exhibits a unique two-dimensional nano-sheet morphology. As a result, the SnSbSx/PCNFs can deliver a high reversible capacity of 566.7 mAh g(-1) after 80 cycles and achieve good cycling stability and rate capability when used as anode materials for SIBs. The improved electrochemical performance of SnSbSx/PCNFs can be ascribed to the synergistic effects of SnSbSx nano-sheets and enhanced diffusion coefficient of Na+ in sulfurated PCNFs (SPCNFs), which can not only provide good electronic conductivity but also buffer the volume change of the SnSbSx nanosheets during sodiation/desodiation process. Additionally, the sulfuration process generates a sulfur doping effect on the PCNFs, further enhancing their sodium storage ability. Therefore, the excellent Na-storage ability demonstrates SnSbSx/PCNFs a great potential as anode material for high-performance SIBs. (C) 2017 Elsevier Ltd. All rights reserved.