Modulating Local Ion Environments for Durable and Dendrite-Free Zinc Metal Anodes

Aqueous zinc-metal batteries (ZMBs) have emerged as promising candidates for large-scale energy storage owing to their intrinsic safety, low cost, and high theoretical capacity.However, uncontrolled growth of Zn dendrites and parasitic side reactions remain critical obstacles, leading to poor reversibility and short-circuit failure.Here, we present that regulating interfacial Zn 2+ transport effectively stabilizes Zn metal anodes, enabled by an ionselective metal-organic framework (MOF) interlayer.Owing to its sub-nanometer pores and chemical stability in acidic aqueous electrolytes, the MOF interlayer enables preferential Zn 2+ transport while restricting the migration of larger anions.Electrochemical simulations confirm that the MOF interlayer homogenizes Zn 2+ flux and alleviates local current hotspots, thereby suppressing dendritic growth.Experimentally, the MOF composite membrane exhibited an increased Zn 2+ transference number (0.72) compared with pristine glass fiber membrane (0.52), validating its preferential Zn 2+ conduction.Zn-symmetric cells equipped with the MOF interlayer demonstrated dendrite-free Zn deposition, reduced hydrogen evolution and corrosion, and extended cycling stability.Post-mortem analyses further revealed significantly suppressed formation of Zn4SO4(OH)6xH2O by-products and a smooth Zn surface morphology, in contrast to the porous and flaky deposits observed with pristine glass fiber membrane.These results underscore the importance of interfacial Zn 2+ flux redistribution in stabilizing Zn anodes and mitigating degradation pathways.This work provides mechanistic insight into interlayer-assisted ion transport regulation, offering a practical strategy for achieving durable Zn plating-stripping behavior in aqueous ZMBs.