Jahn–Teller Distortion Induced Mn<sup>2+</sup>‐Rich Cathode Enables Optimal Flexible Aqueous High‐Voltage Zn‐Mn Batteries
Lixin Dai, Yan Wang, Lu Sun, Yi Ding, Yuanqing Yao, Lide Yao, Nicholas E. Drewett, Wei Zhang, Jun Tang, Weitao Zheng
Abstract
Abstract Although one of the most promising aqueous batteries, all Zn‐Mn systems suffer from Zn dendrites and the low‐capacity Mn 4+ /Mn 3+ process (readily leading to the occurrence of Jahn–Teller distortion, which in turn causes structural collapse and voltage/capacity fading). Here, the Mn 3+ reconstruction and disproportionation are exploited to prepare the stable, Mn 2+ ‐rich manganese oxides on carbon‐cloth (CMOs) in a discharged state through an inverted design, which promotes reversible Mn 2+ /Mn 4+ kinetics and mitigates oxygen‐related redox activity. Such a 1.65 V Mn 2+ ‐rich cathode enable constructing a 2.2 V Zn‐Mn battery, providing a high area capacity of 4.16 mA h cm –2 (25 mA h cm –2 for 10 mL electrolyte) and superior 4000‐cycle stability. Moreover, a flexible hybrid 2.7 V Zn‐Mn battery is constructed using 2‐pH hydrogel electrolytes to demonstrate excellent practicality and stability. A further insight has been gained to the commercial application of aqueous energy storage devices toward low‐cost, high safety, and excellent energy density.