Free-standing SnS/C nanofiber anodes for ultralong cycle-life lithium-ion batteries and sodium-ion batteries

The development of flexible energy storage devices is the key to widen the application of flexible electronics and wearable devices . Flexible electrodes with superior electrochemical performance are critical components for flexible energy storage devices. Herein, we propose a simple and versatile electrospinning strategy to prepare the SnS/C nanofibers (SnS/C NFs) film. By using SnS/C NFs film directly as a free-standing anode in both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), it can provide outstanding electrochemical performance. For LIBs, it delivers high capacities of 648 and 548 mA h g -1 at 200 and 500 mA g -1 respectively after 500 cycles. It even shows outstanding cyclability for 1000 cycles. For SIBs, it retains capacity of 481 mA h g -1 after 100 cycles at 50 mA g -1 . Moreover, the capacity remains as high as 349 mA h g -1 at 200 mA g -1 after 500 cycles. The outstanding electrochemical performance is mainly attributed to the fact that the fine SnS nanoparticles dispersed in one-dimensional porous nanofibers with uniform diameters around 130 nm shorten the transport path of ions and electrons, and the presence of N-doped carbon enhanced the electrical conductivity as well as relieve the volume change caused by the alloying/de-alloying reaction. Besides, the ultra-robust mechanical flexibility of SnS/C NFs film makes it a promising anode candidate for flexible LIB and SIB in future.