Synergistically Accelerating Zn ²⁺ Transport and Desolvation Through Cation‐Deficient Ion Channels in High‐Performance Zn Metal Batteries

ABSTRACT Aqueous Zn metal batteries (ZMBs) are promising for grid‐scale energy storage. However, their commercialization is hindered by issues such as Zn dendrite formation and parasitic side reactions. These problems stem from sluggish and uneven Zn ²⁺ flux and the strong hydration shell of Zn ²⁺ in aqueous electrolytes. To address these challenges, we present a multifunctional ion channel using indium‐intercalated titanium oxide (In‐Ti _0.87 O ₂ ; ITO) as a protective layer on a Zn anode. The ITO layer, synthesized via a simple cation‐exchange process, exhibits a negatively charged surface and zincophilic indium sites within its wide interlayer channels. Unlike conventional ion channels, which primarily operate via the desolvation effect, this unique channel structure simultaneously offers a low energy barrier for Zn ²⁺ desolvation and enhanced Zn ²⁺ transport kinetics. Consequently, the ITO‐coated Zn anode demonstrates exceptional electrochemical performance, including superior cycle stability over 6000 h in a symmetric cell at 2 mA cm ^–2 with a low overpotential of 12 mV. Furthermore, a full cell paired with an MnO ₂ cathode exhibites superior rate capability and reversibility under practical conditions. This study presents a novel and effective strategy for designing advanced ion channels that simultaneously facilitate desolvation and ion transport, paving the way for commercially viable ZMBs.