Interfacial engineering-enabled activation-free Zn2+-dominated kinetics in MnO2 cathodes for aqueous zinc-ion batteries

초록

The growing energy demand of AI-driven data centers requires the development of safe and reliable energy storage systems. Aqueous zinc-ion batteries (AZIBs) are promising candidates in this area, owing to their intrinsic safety; however, MnO2 cathodes suffer from sluggish Zn2+ diffusion and require an activation process, limiting their practical performance. Herein, we propose a Zn2+ insertion-accelerated (ZIA) cathode enabled by a polyethylene oxide (PEO) interfacial layer to regulate the ion transport behavior. The PEO layer enhances electrolyte wettability, reduces interfacial resistance, and accelerates Zn2+ diffusion while suppressing competitive transport of H+ ions. As a result, a Zn2+-dominated reaction pathway is established from the first cycle, limiting irreversible phase transitions (such as MnOOH formation) and promoting uniform electrochemical utilization throughout the electrode. The ZIA cathode exhibits high capacity, superior rate capability, and stable long-term cycling, accompanied by reduced Mn dissolution and improved structural integrity. Interfacial engineering governs the bulk reaction kinetics and stabilizes the MnO2 framework. This work demonstrates that controlling interfacial ion transport is an effective strategy to overcome intrinsic kinetic limitations, providing a viable pathway toward safe and high-performance AZIB-based energy storage systems. © 2026

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