Decoupling Bulk Kinetics and Surface Stability: A Dual-Regulation Strategy for High-Performance Ammonium Vanadate...

Aqueous zinc-ion batteries (AZIBs) hold promise for sustainable energy storage, but high-capacity ammonium vanadate (NH₄V₄O₁₀, NVO) cathodes suffer from sluggish Zn²⁺ kinetics and structural degradation via vanadium dissolution. To overcome these persistent bottlenecks, we propose a decoupled dual-modification strategy integrating the controlled partial substitution of interlayer NH₄ ⁺ with hydronium ions (H₃O⁺) and the in-situ formation of a conformal poly(3,4-ethylenedioxythiophene) (PEDOT) conductive network. Mechanistic and density functional theory (DFT) studies reveal that acid-induced proton exchange expands the interlayer spacing, significantly lowering the Zn²⁺ diffusion barrier. Conversely, the PEDOT coating acts as a "structural-electronic" bridge, compensating for the conductivity loss associated with deammoniation while serving as a robust physical barrier that suppresses the formation of the electrochemically inactive Zn₃(OH)₂V₂O₇·2H₂O passivation layer. The resulting NVO@PEDOT cathode delivers an exceptional specific capacity of 360.2 mAh g^-1, superior rate capability (110 mAh g^-1 at an ultra-high current density of 30 A g^-1), and remarkably robust cycling stability. It retains 94.0% of the capacity after 200 cycles at 0.5 A g^-1 and 69.2% after 10 000 cycles at a high rate of 15 A g^-1. This work establishes a versatile design strategy for decoupling kinetic and stability challenges in the cathode, paving the way for practical, high-rate AZIBs.