“Three‐in‐One” Strategy that Ensures V2O5·nH2O with Superior Zn2+ Storage by Simultaneous Protonated Polyaniline Intercalation and Encapsulation

Abstract

The structural engineering of vanadium oxides is considered as a research hotspot for enhancing their electrochemical performances applied to aqueous zinc‐ion batteries (AZIBs). In regard to the laggard Zn2+ transfer kinetic and fragile structure of V2O5·nH2O, herein, a feasible “three‐in‐one” strategy is adopted to design the structural engineering of V2O5·nH2O nanobelts through simultaneous protonated polyaniline intercalation and encapsulation (denoted as P‐VOH@P) to boost their Zn2+ storage. First, the enlarged interlayer pillared by polyaniline accelerates Zn2+ transfer speed and weakens electrostatic attraction between negative [VO] units and positive Zn2+. Second, polyaniline shell directly stabilizes the P‐VOH@P heterostructure. Third, the composition of protonated polyaniline not only improves the conductivity, but also contributes partial capacity though the reversible intrachain electronic migration. As expected, the Zn//P‐VOH@P cell exhibits specific capacities of 387 mAh g−1 with low‐mass‐loading cathode (2 mg cm−2) and 345 mAh g−1 with high‐mass‐loading cathode (5 mg cm−2) in coin cells and 360 mAh g−1 in pouch cells at 0.1 A g−1. Furthermore, the Zn//P‐VOH@P cell shows low capacity decay and good rate property. Herein, light is shed on a new strategy of engineering the vanadium oxide structure for postgeneration cathode material and paves a novel way to the advanced energy‐storage system.