Large-area hydrated vanadium oxide/carbon nanotube composite films for high-performance aqueous zinc-ion batteries

Synchronously reducing/self-assembling strategy on Zn substrate was designed to fabricate large-area cation-doped hydrated V2O5/multi-walled carbon nanotube (D-HVO/MWCNT) composite films. Interestingly, the Zn2+ ions are simultaneously doped in hydrated V2O5 during the assembly process, which will be beneficial to the high electrochemical performance of hydrated V2O5. By further combining 3D conductive MWCNT network, the freestanding D-HVO/MWCNT composite films display high capacity, excellent rate capability, and remarkable long-term cycling performance (up to 10,000 cycles with a high capacity retention of 98.5%). Moreover, owing to the high conductivity and flexibility of the D-HVO/MWCNT composite films, the soft-packaged aqueous zinc-ion batteries (ZIBs) were constructed based on such composite films. The devices exhibit stable electrochemical performance even under different bending states. Therefore, such a strategy provides a promising route to achieve large-area carbon and metal oxides-based composite films with high performance and good flexibility.