Conductive Polypyrrole-Encapsulated Vanadium Trioxide for High-Performance Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are regarded as appealing electrochemical storage systems because of their intrinsic safety and environmental compatibility. Nevertheless, the practical use of V2O3 cathodes remains challenging because of the intense electrostatic coupling of Zn2+ with the V2O3 crystal lattice, as well as slow reaction kinetics. In the present study, a core–shell composite (V2O3@ppy) is developed via an in situ polymerization strategy to mitigate the limitations associated with V2O3. V2O3 microspheres consisting of self-assembled nanoparticles are first prepared by a solvothermal method, and then, a conductive polypyrrole (ppy) shell is deposited through low-temperature polymerization to construct the core–shell structure. The uniform conductive ppy coating on the surface of V2O3 markedly improves electronic and ionic transportation properties and cycling durability of V2O3@ppy. When employed as a cathode in AZIBs, the V2O3@ppy composite exhibits a large specific capacity reaching 453.6 mAh g–1 at 0.1 A g–1, strong rate performance delivering 170.3 mAh g–1 at 10 A g–1, and durable cycling performance, preserving 64.7% (compared with the first cycle at 10 A g–1) of its capacity over 1000 cycles. The improved electrochemical properties confirm that the in situ polymer encapsulation strategy effectively promotes Zn2+ diffusion while reinforcing the electrode structural integrity. This work provides an effective organic/inorganic interface-tailoring route for constructing high-performance cathodes with accelerated reaction kinetics and prolonged cycling durability.