Engineering Interlayer Space and Composite of Square-Shaped V₂O₅ by PVP-Assisted Polyaniline Intercalation and...

V₂O₅ undergoes irreversible phase transition and collapse of layered structure during the Zn²⁺ insertion/extraction, which severely limits its application as a cathode for aqueous zinc-ion batteries (AZIBs). Herein, a synergistic strategy of conductive polyaniline insertion and graphene composite was proposed to boost the Zn²⁺ storage performance of the V₂O₅ cathode. A square-shaped polyaniline (PANI)-intercalated and graphene-composited vanadium oxide (GO/PANI-PVP/V₂O₅) structure was successfully synthesized via an in situ oxidation/insertion polymerization combined with a hydrothermal method. The results showed that PANI intercalation and the composite of graphene combined with layered V₂O₅, enabling reversible intercalation of Zn²⁺/H⁺. The insertion of conjugated PANI not only increases the lattice spacing of V₂O₅, providing a channel for rapid transport of Zn²⁺, but also increases the storage sites for charges through doping/dedoping processes and redox conversion reactions. GO/PANI-PVP/V₂O₅ delivers an excellent specific capacity (495 mA h g^-1 at 0.1 A g^-1), wonderful rate capability (208 mA h g^-1 at 30 A g^-1), and good cycling stability (93% after 4000 cycles). Our results provide a new approach for adjusting the valence states, interlayer spacing, and rational design of organic-inorganic compound materials for different functional materials.