Hierarchical WS2/C nanofibers with controlled interlayer spacing for high-performance sodium ion batteries

Hierarchical WS2/C nanofibers with controllable layer spacing are prepared by electrospinning combined with in-situ sulfurization at 800 degrees C. The characterizations reveal that WS2 is uniformly embedded in the nanofibers; as well as adhering to the nanofiber surface with large layer spacing (0.76 nm). The hierarchical structure promotes rapid diffusion of Na+ and has a large contact area with the electrolytes, which improves the capacity of sodium-ion batteries (SIBs). As a result, the obtained WS2/C nanofiber electrode has high capacity and excellent cyclic stability. It demonstrates a special discharge capacity of 291 mAh g-1 with capacity retention of 99.1 % at the 200th cycle at a current density of 0.5 A g-1, even maintaining 159 mAh g-1 after 1000 cycles at 5 A g-1. Furthermore, theoretical calculations using the density functional theory (DFT) demonstrate that the WS2/C500-800 electrode obtained by annealing at 500 degrees C and vulcanization at 800 degrees C is conducive to Na+ storage. This work provides a solid theoretical basis for the industrialization of high specific capacity SIB anodes and the research of energy storage electronic devices.(c) 2023 Elsevier B.V. All rights reserved.