Design of large-spacing, high-stability PANI-NixV2O5 nanobelts as cathode for aqueous zinc-ion batteries using an organic-inorganic co-embedding strategy

Aqueous zinc-ion batteries (AZIBs), distinguished by their high safety and cost-effectiveness, hold significant promise for grid-level energy storage systems. However, the strong interactions between zinc ions and the host lattice of materials lead to suboptimal cycling stability and rate performance. To address this, we present a novel superlattice structure incorporating conductive polymer (PANI) and metal cation (Ni2+) double interlayers, which can be utilized as cathodes for AZIBs. The incorporation of the conductive host polymer polyaniline (PANI) reduces the valence state of vanadium, enhances the electrical conductivity, and effectively expands the channels for zinc ion insertion. Additionally, metal cations (Ni2+) can effectively induce the synergistic interactions with zinc ions, thereby mitigating the electrostatic interactions with the V2O5 host. Consequently, the assembled Zn//PANI-NixV2O5 (PNV) battery exhibits a specific capacity of up to 470 mAh g−1 at 0.1 A g−1, and retains 89.5 % of its capacity after 1000 cycles at 5 A g−1. A two-step intercalation approach was employed, wherein Ni ions and aniline molecules were sequentially inserted into the V2O5 layers, followed by in situ polymerization of aniline within these layers, yielding PANI-NixV2O5 nanobelts. This organic-inorganic dual intercalation strategy effectively expanded the interlayer spacing of V2O5 to 13.4 Å, thereby significantly enhancing its electrochemical performance. [Display omitted] •A novel organic-inorganic bilayered vanadium oxide was proposed as the cathode for ZIBs.•PANI-NixV2O5 nanobelts has an expanded interlayer spacing of 13.468 Å.•The PANI-NixV2O5 cathode used for AZIBs exhibits a specific capacity of up to 470 mAh g−1.