High energy density flexible zinc–ion batteries enabled by polyaniline-encapsulated molybdenum-doped tungsten oxide nanorods as a zinc intercalation electrode

With the rising technology of flexible and wearable portable smart devices, aqueous rechargeable zinc–ion batteries (ZIBs) are one of the potential candidates as energy storage devices, however, the uncontrollable growth of Zn dendrites owing to the uneven deposition of zinc during charging, and the scarcity of high-performance electrodes limit the development of high-performance flexible ZIBs. Herein, a novel PANI@WMoO₃ nanorods (NRs) core–shell nanostructure is designed as an intercalation electrode for the development of aqueous flexible ZIBs. Advancing from a PANI buffer layer and accelerating Zn²⁺ ion insertion/extraction owing to the hexagonal crystalline structure of WMoO₃, the PANI@WMoO₃//Zn/CC battery exhibits outstanding electrochemical performance, with a high specific capacity of 329.0 mA·h/g at 0.2 A/g, exceptional rate capability, and superior cyclic stability (∼90.09 % after 1,000 cycles). In addition, the fabricated flexible ZIBs demonstrate excellent mechanical characteristics. Moreover, the ZIBs deliver a high energy density of 394.8 W·h/kg at a power density of 141.6 W/kg. Additionally, a Zn metal-free aqueous Zn-ion battery is successfully assembled with PANI@WMoO₃ NRs/CC as anode and a ZnMnO₄ as cathode, which exhibits an excellent specific capacity of 247.3 mA·h/g at 0.2 A/g, good rate capability and cyclic stability (∼94.7 % after 1,000 cycles), signifying the practicability of PANI@WMoO₃ NRs/CC as an intercalated anode for Zn²⁺ ion full batteries.