Binder Engineering Suppresses Jahn-Teller-Driven Mn Dissolution and Enables High-Loading MnO2 Cathodes for Aqueous Zn-Ion Batteries

초록

The rapid growth of artificial intelligence (AI)-driven data centers has intensified demand for scalable, safe, and high-performance energy storage systems (ESSs). Aqueous zinc-ion batteries (AZIBs) are attractive candidates due to their intrinsic safety and the high theoretical capacity of zinc metal anodes. However, their practical deployment in ESSs is limited by two key challenges: pronounced Mn dissolution from beta-MnO2 cathodes induced by Jahn-Teller distortion during cycling, and low areal energy density resulting from the poor electrochemical performance of thick electrodes produced by conventional wet-processing methods. In this work, we propose a simple yet effective binder-engineering strategy based on a Zn2+-coordinated poly(vinylidene fluoride) (PVDF/Zn2+) system. The Zn2+ coordination stabilizes the MnO2 structure by suppressing Jahn-Teller distortion while simultaneously improving binder dispersion and electrode wettability. These effects enable the fabrication of thick cathodes with a uniform microstructure and strong mechanical integrity. Consequently, the PVDF/Zn2+-based cathodes exhibit high specific and areal capacities (0.9 mAh cm-2 after 400 cycles at 1C) and superior rate capability at high mass loading (similar to 9.7 mg cm-2). Overall, this study introduces a material-efficient strategy for enhancing the structural stability and electrochemical robustness of AZIBs, providing a promising platform for grid-scale and AI-infrastructure applications.

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