Fabrication of a Robust and Porous MnO2 Electrode as the Cathode for High‐Performance Aqueous Zinc‐Ion Batteries

Abstract

Due to their excellent qualities (cheaper raw materials, convenient fabrication method, and high level of safety) of aqueous Zn–MnO2 batteries, they have aroused interest as potential replacements for lithium‐ion batteries. However, the sluggish electron/ion‐transfer rate of MnO2 cathodes hinders their further application as energy‐storage devices. Hence, a simple preparation method is proposed for MnO2 cathodes with porous structures that can effectively reduce the difficulty of electron/ion migration inside an electrode. In addition, the filamentous poly(1,1‐difluoroethylene) generated during the preparation process can act as a supporting structure in the cathode, which maintains the structural stability of the MnO2 cathode, even enduring long‐term charge/discharge cycles. Thus, this cathode has great Zn2+‐storage performance: a high specific capacity of 313 mAh g−1 at 0.1 A g−1 and an impressive rate capability of 106.4 mAh g−1 at an ultrahigh current density of 5 A g−1. In particular, the cathode exhibited superior cycling stability with 69.7% capacity retention after 800 cycles at 3 A g−1. In addition, this cathode presents excellent comprehensive performance of energy conservation. In this method, a versatile approach may be provided for producing cathodes with superior performance in aqueous zinc‐ion batteries systems.