Synthesis of three-dimensional free-standing WSe2/C hybrid nanofibers as anodes for high-capacity lithium/sodium ion batteries

Although there is great progress in the exploration of high capacity alkali metal ion batteries in recent years, the design of high-durable anode materials with high power density remains challenging. In this research, a flexible three-dimensional network of WSe2/C is reported as dual-role anode for lithium/sodium ion batteries, providing multichannel for the fast lithium/sodium ion diffusion and the buffer matrix to restrain the volume change, as well as increase the electron conductivity. The in-situ transmission electron microscopy characterizations reveal minor volume expansion of the WSe2/C (~8.2%) and a complete-amorphization event occurring after the first lithiation process. The WSe2/C exhibits superior reversible capacity/rate capability/cycling stability in the lithium/sodium ion batteries. Especially, a large stable capacity and ultra-long cycling life at ultra-high rate (257.0 mAh g-1 at 25 A g-1 after 10000 cycles) are achieved in WSe2/C electrode in lithium ion batteries, accompanied with only 0.5% capacity loss per cycle when compared to the 1000 cycles, which reveals the excellent capacity stability in the ultra-high rate. This study reveals the great potential of WSe2/C as high-capacity dual-role anode for lithium/sodium ions batteries.