Rational hierarchical micellar gel electrolytes with synergistic hydrophobic–hydrophilic integration for dendrite-free zinc-ion batteries

Abstract

The uncontrolled dendritic growth and severe side reactions significantly constrain zinc-ion batteries' further application. This study presents a novel micellar gel electrolyte, innovatively designed through hydrophobic association. The micellar gel electrolyte harmonizes macroscopic and microscopic properties through a rational hierarchical design. At the macroscopic level, the hydrophilic domains as water-absorbing nets and the hydrophobic domains as pillars are intricately interwoven. On the microscopic scale, the copolymerization resulted in a microphase-separated architecture, with hydrophilic and hydrophobic domains establishing distinct micro-regions within the gel matrix. The hydrophilic domains contribute to the stabilization of the hydrogen bond network through amide groups, while the abundant carbonyl groups optimize the solvation structure and migration pathways of Zn²⁺. The hydrophobic domains provide a robust supporting framework while simultaneously reducing H₂O activity and thereby minimizing parasitic reactions. Thus, the enhanced interfacial stability forms a robust and flexible barrier against dendrite formation. The rational hierarchical gel composition and cross-linked network effectively direct Zn deposition preferentially along the (002) plane, ensuring a uniform and stable interface. The assembled Zn‖MnO₂ batteries show 80% capacity retention after 1200 cycles at 1C.