Engineering Interlayer Space and Composite of Square-Shaped V₂O₅ by PVP-Assisted Polyaniline Intercalation and Graphene for Aqueous Zinc-Ion Batteries

Abstract

V 2 O 5 undergoes irreversible phase transition and collapse of layered structure during the Zn 2+ 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 Zn 2+ storage performance of the V 2 O 5 cathode. A square-shaped polyaniline (PANI)-intercalated and graphene-composited vanadium oxide (GO/PANI-PVP/ V 2 O 5 ) 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 V 2 O 5 , enabling reversible intercalation of Zn 2+ /H + . The insertion of conjugated PANI not only increases the lattice spacing of V 2 O 5 , providing a channel for rapid transport of Zn 2+ , but also increases the storage sites for charges through doping/ dedoping processes and redox conversion reactions. GO/PANI-PVP/V 2 O 5 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.