Gradient Zincophilic-Hydrophobic separator for Zn2+/H+ transport decoupling towards Ultrastable zinc anodes

Aqueous zinc metal batteries (AZMBs) are promising for next-generation storage due to safety, low cost, and eco-friendliness, but suffer from Zn dendrites and hydrogen evolution. Here, a gradient zincophilic-hydrophobic (GF@PFA) separator is fabricated via capillary adsorption and in-situ polymerization. Its top retains GF hydrophilicity for electrolyte wetting, while the polyfurfuryl alcohol (PFA) coating at the bottom, rich in C-O groups, guides uniform Zn 2+ deposition. Simultaneously, the hydrophobic framework blocks H 2 O contact with the Zn anode, impeding H + migration. This decouples Zn 2+ /H + transport paths, optimizing ion dynamics and interface stability. Therefore, the Zn||Zn symmetrical battery achieved an 1800 h cycle at 2 mA cm −2 /2 mAh cm −2 , which was more than 8 times higher than that of the original GF. The Zn||ZnS full cell delivers 633.5 mAh g −1 and 99.7 % CE at 0.5 A g −1 , retaining 81 % capacity after 1350 cycles. This work confirms that the design of gradient functionalized separators can collaboratively solve the multi-scale interface imbalance problem of zinc anodes, providing an innovative strategy and theoretical basis for the development of long-life AZMBs.