A hydrophobic phenolic polymer layer with high-flux Zn2+-specific regular channels for stabilizing aqueous zinc anodes

Abstract

The persistent issues of dendrite growth and side reactions have been major obstacles hampering practical applications of aqueous zinc-ion batteries (AZBs). Herein, a porous phenolic resin (PPR) artificial protective layer integrated hydrophobic framework with regular channels is constructed on Zn foil (PPR@Zn) to stabilize the Zn anode. Experimental and theoretical calculations demonstrate that the PPR@Zn layer is endowed with the following functions: (i) Zn²⁺ dedicated channels of PPR provide uniform diffusion pathways for Zn²⁺. The high ion conductivity (7.7 mS cm⁻¹) and Zn²⁺ transference number (0.86) prevent localized over-deposition of Zn and improve the reaction kinetics. (ii) The affinity of PPR with Zn²⁺ decreases the desolvation barrier of [Zn(6H₂O)]²⁺ and promotes rapid and uniform Zn deposition. (iii) The repulsion of H₂O molecules and SO₄²⁻ anions inhibits the corrosion and side reaction. (iv) Uniform space electric fields on the anode surface mitigate the “tip effect”. These synergistic effects lead to dendrite-free Zn deposition. As a result, symmetrical cells assembled with PPR@Zn demonstrate an ultra-long cycle life of 4200 h. For practical applications, pairing with an MnO₂ cathode, the full cells also achieved excellent cycling stability and rate performance. This work presents a promising strategy for designing corrosion-resistant, high-stability, and reversible metal anodes.