MXene-Stabilized VS 2 Nanostructures for High-Performance Aqueous Zinc Ion Storage.

Aqueous zinc-ion batteries (AZIBs) based on vanadium oxides or sulfides are promising candidates for large-scale rechargeable energy storage due to their ease of fabrication, low cost, and high safety. However, the commercial application of vanadium-based electrode materials has been hindered by challenging problems such as poor cyclability and low-rate performance. To this regard, sophisticated nanostructure engineering technology is used to adeptly incorporate VS 2 nanosheets into the MXene interlayers to create a stable 2D heterogeneous layered structure. The MXene nanosheets exhibit stable interactions with VS 2 nanosheets, while intercalation between nanosheets effectively increases the interlayer spacing, further enhancing their stability in AZIBs. Benefiting from the heterogeneous layered structure with high conductivity, excellent electron/ion transport, and abundant reactive sites, the free-standing VS 2 /Ti 3 C 2 T z composite film can be used as both the cathode and the anode of AZIBs. Specifically, the VS 2 /Ti 3 C 2 T z cathode presents a high specific capacity of 285 mAh g -1 at 0.2 A g -1 . Furthermore, the flexible Zn-metal free in-plane VS 2 /Ti 3 C 2 T z //MnO 2 /CNT AZIBs deliver high operation voltage (2.0 V) and impressive long-term cycling stability (with a capacity retention of 97% after 5000 cycles) which outperforms almost all reported Vanadium-based electrodes for AZIBs. The effective modulation of the material structure through nanocomposite engineering effectively enhances the stability of VS 2 , which shows great potential in Zn 2+ storage. This work will hasten and stimulate further development of such composite material in the direction of energy storage.