Heterogeneous Electric Double Layer with Ion‐Transport Pathways for Practical Zinc‐Ion Batteries

ABSTRACT Manipulating the electric double layer (EDL) structure at nanoscale remains largely underexplored yet extremely challenging for practical Ah‐level aqueous zinc‐ion batteries (AZIBs). Here, we construct a heterogeneous nanostructured EDL with intrinsic ion‐transport pathways via cation‐anion coordination strategy, which synergistically enhances the thermodynamic stability and kinetic reversibility of the Zn anode. In‐situ characterizations and theoretical simulations demonstrate that the long‐chain ionic additive triggers the interfacial ion rearrangement and assembly within the EDL, where hydrophobic carbon chains self‐aggregate into dense apolar nanodomains, and cationic groups electrostatically attract anions and co‐assemble to form interconnected polar nanodomains. This uniquely heterogeneous EDL thermodynamically confines H 2 O activity and efficiently inhibits side reactions. Meanwhile, the interconnected polar ion‐transport pathways accelerate Zn 2+ migration and desolvation kinetics, achieving an ultrahigh Zn 2+ transference number (0.89) and dendrite‐free Zn deposition. Consequently, Zn//Zn cell delivers stable cycling over 1,200 h (25 mA cm −2 , 12.5 mAh cm −2 ) and Zn//NVO full cell retains 100% capacity after 30,000 cycles at 5 A g −1 . Furthermore, 0.2‐Ah and 1.1‐Ah pouch cells exhibit stable operation for 2,500 and 257 cycles, respectively. This work establishes a new paradigm for EDL nanostructure engineering, advancing practical AZIBs.