Regulating Structural and Electronic Coupling in Layered Vanadium Oxide via La ³⁺ and Polyaniline for High-Stability Aqueous Zinc-Ion Storage

Regulating structural and electronic coupling in layered vanadium oxide is crucial for achieving high stability and fast reaction kinetics in aqueous zinc-ion batteries (ZIBs). Herein, we engineer a layered vanadium oxide cathode (LaPVO) through the intercalation of La3+ and in situ polymerized polyaniline (PANI) into the vanadium oxide framework. The La3+ functions as rigid structural pillars that expand and stabilize the interlayer spacing, while the conjugated PANI chains establish continuous electronic pathways and buffer mechanical strain. Through this interlayer regulation, the structural and electronic coupling within the vanadium oxide host is effectively reinforced, thereby accelerating Zn2+ diffusion, enhancing charge transport, and suppressing phase degradation during prolonged cycling. Comprehensive structural and spectroscopic characterizations verify the successful cointercalation of La3+ and PANI, accompanied by an increased V4+ content and pronounced interfacial charge redistribution. Owing to the synergistic structural-electronic regulation, the LaPVO cathode delivers a high reversible capacity of 358 mAh g–1 at 0.3 A g–1 and exhibits remarkable cycling stability, retaining 331 mAh g–1 after 200 cycles and 209 mAh g–1 after 1000 cycles. In addition, LaPVO demonstrates outstanding rate capability with minimal capacity decay under high current densities. Density functional theory calculations reveal strengthened Zn2+ adsorption, an increased density of electronic states near the Fermi level, and reduced Zn2+ migration energy barriers, providing fundamental insight into the experimentally observed performance enhancement. This work establishes a general and effective interlayer engineering strategy for designing robust vanadium-based cathodes, offering new opportunities for grid-relevant aqueous ZIBs.