Regulating the Gibbs Free Energy to Design Aqueous Battery‐Compatible Robust Host

Abstract

AbstractLow‐cost, high‐voltage‐platform, and high‐capacity MnO2 is the most promising cathode candidate for developing high‐energy‐density aqueous zinc‐ion batteries. However, the Buckets effect of runaway phase transition and irreversible dissolution restricts the electrochemical performance of MnO2. To address this issue, this report presents a bottom‐up targeted assembly concept driven by Gibbs free energy for the design of a robust Ni‐MnO2‐xFx host via Ni2+ pre‐intercalation coupled with fluorine doping. The Gibbs free energy of the host is regulated by the coordination of interlayer reinforcement and interfacial defect repair, which prevents the “layer‐to‐spinel” transition and inhibits dissolution during long‐term cycling. As expected, this cathode provides superior H+/Zn2+ storage performance across a wide temperature range. A capacity of 180.4 mAh g−1 is retained after 1000 cycles at 2 A g−1, a high specific capacity of 293.9 mAh g−1 is retained after 250 cycles at 50 °C and 2 A g−1, and a capacity of 144.5 mAh g−1 is retained after 3000 cycles at 0 °C and 0.5 A g−1. This work provides new insights into the design of stable aqueous battery‐compatible hosts for aqueous zinc‐ion batteries as well as other battery chemistries.