WS2 Nanowires as a High-Performance Anode for Sodium-Ion Batteries

We report the synthesis and anode application for sodium-ion batteries (SIBs) of WS 2 nanowires (WS 2 NWs). WS 2 NWs with very thin diameter of ≈25 nm and expanded interlayer spacing of 0.83 nm were prepared by using a facile solvothermal method followed by a heat treatment. The as-prepared WS 2 NWs were evaluated as anode materials of SIBs in two potential windows of 0.01–2.5 V and 0.5–3 V. WS 2 NWs displayed a remarkable capacity (605.3 mA h g −1 at 100 mA g −1 ) but with irreversible conversion reaction in the potential window of 0.01–2.5 V. In comparison, WS 2 NWs showed a reversible intercalation mechanism in the potential window of 0.5–3 V, in which the nanowire-framework is well maintained. In the latter case, the interlayers of WS 2 are gradually expanded and exfoliated during repeated charge–discharge cycling. This not only provides more active sites and open channels for the intercalation of Na + but also facilitates the electronic and ionic diffusion. Therefore, WS 2 NWs exhibited an ultra-long cycle life with high capacity and rate capability in the potential window of 0.5–3 V. This study shows that WS 2 NWs are promising as the anode materials of room-temperature SIBs. Graphical WS 2 nanowires with very thin diameters (≈25 nm) and expanded interlayer spacing (0.83 nm) were synthesized by using a facile solvothermal method followed by heat treatment. This distinctive nanostructure exhibits an ultra-long cycle life with high capacity and rate capability as anode material of sodium-ion batteries (see figure).