Harnessing Polymer Matrix Hydrophilicity in Structurally Robust Zincophilic Composite Layers for High-Performance...

Aqueous zinc-ion batteries (AZIBs) represent promising next-generation energy-storage systems owing to their intrinsic safety afforded by water-based electrolytes, low material costs, and high theoretical capacity. However, uncontrolled dendrite growth with nonuniform Zn²⁺ flux at the electrode-electrolyte interface severely impedes their practical implementation. In this work, we develop a zincophilic-hydrophilic polymer composite layer to regulate Zn deposition via coordinated ionic and electronic transport. The integration of the hydrophilic poly(acrylic acid) (PAA) with a zincophilic carbon black filler forms an ionically and electronically conductive protective layer on the Zn anode. This zincophilic polymer composite (ZLPC) layer facilitates efficient electrolyte wetting throughout the composite network, thereby activating internal zincophilic sites and homogenizing Zn²⁺ flux across the electrode-electrolyte interface. This synergistic ionic and electronic regulation mitigates localized current density and induces uniform Zn nucleation, yielding dendrite-free Zn deposition. Consequently, the ZLPC@Zn anode achieves a cycling life exceeding 3000 h at 4 mA cm^-2, with a cumulative plating capacity of 2400 mAh cm^-2. Furthermore, ZLPC@Zn pouch cells exhibit a volumetric energy density of 17.92 Wh L^-1, demonstrating strong potential for practical AZIB applications. This study presents a scalable, cost-effective interfacial engineering strategy for high-performance AZIBs.