Freestanding H 2 V 3 O 8 /MXene films for high performance quasi-solid-state zinc-ion batteries

In this study, freestanding H 2 V 3 O 8 /MXene (HVO/MX) film were synthesized by high temperature mixing hydrothermal method and coating method. The composite film exhibits good electrical conductivity and flexibility. In addition, HVO/MX film shows excellent electrochemical properties when used as cathode material for aqueous zinc ion batteries (ZIBs) and solid-state ZIBs. The aqueous ZIBs assembled from the HVO/MX film shows satisfactory specific capacity (highest specific capacity can reach 346 mAh/g at 10 A/g) and cycling performance. Surprisingly, the assembled quasi-solid-state batteries can work well at room temperature and low temperature conditions. The battery maintained a high discharge specific capacity of 180 mAh/g after 3000 cycles at 25 °C. The outstanding performance of the HVO/MX film assembled battery is due to its good electrical conductivity, zinc-ion diffusion rate and simple battery structure. This work provides a novel route for the preparation of self-supporting cathode materials for different battery system.