Chaotropic Anion‐Regulated Interfacial Desolvation Enables Ultrafast Aqueous Zn‐Ion Storage in TiN‐Integrated δ‐MnO ₂ /MXene Heterostructure Anodes

ABSTRACT Aqueous zinc‐ion hybrid supercapacitors (AZI‐HSCs) offer a compelling sustainable energy storage platform, yet their development is constrained by incompatible electrode‐electrolyte dynamics. Sluggish anode kinetics and narrow electrolyte voltage windows fundamentally limit their performance. While δ‐MnO ₂ offers high theoretical capacity as an anode, its practical deployment is hindered by poor conductivity, slow ion diffusion, and structural instability. Herein, an atomic‐scale charge‐modulated δ‐MnO ₂ /MXene–TiN heterostructure anode synergized with a chaotropic ClO ₄ ⁻ ‐modified electrolyte holistically overcomes these limitations. Nitrogen functionalization engineers conductive Ti–N scaffolds within MXene that generate built‐in electric field (BIEF) and modulate interlayer spacing, which synergistically couples with expanded ion channels of δ‐MnO ₂ to enable strain‐free Zn ²⁺ diffusion and ultrafast charge transport. This anode architecture is integrated with a chaotropic ClO ₄ ⁻ ‐modified electrolyte, where the anions preferentially adsorb onto the hydrophobic TiN domains. This synergy disrupts Zn ²⁺ solvation shells to slash the desolvation barrier and expands the operating window by 20%. The assembled full cell (δ‐MnO ₂ /MXene–TiN//δ‐MnO ₂ ) achieves a 2.0 V operating voltage, delivering a high energy density of 87.08 Wh kg ⁻¹ at 1000 W kg ⁻¹ and exceptional cycling stability with 85.8% capacity retention over 12,000 cycles. This work demonstrates how atomic‐scale electrode‐electrolyte co‐design transcends fundamental limitations in aqueous energy storage.