Amorphous Heterostructure Derived from Divalent Manganese Borate for Ultrastable and Ultrafast Aqueous Zinc Ion Storage

Aqueous zinc‐manganese (Zn–Mn) batteries have promising potential in large‐scale energy storage applications since they are highly safe, environment‐friendly, and low‐cost. However, the practicality of Mn‐based materials is plagued by their structural collapse and uncertain energy storage mechanism upon cycling. Herein, this work designs an amorphous manganese borate (a‐MnBO (x) ) material via disordered coordination to alleviate the above issues and improve the electrochemical performance of Zn–Mn batteries. The unique physicochemical characteristic of a‐MnBO (x) enables the inner a‐MnBO (x) to serve as a robust framework in the initial energy storage process. Additionally, the amorphous manganese dioxide, amorphous Zn (x) MnO(OH)(2), and Zn(4)SO(4)(OH)(6)·4H(2)O active components form on the surface of a‐MnBO (x) during the charge/discharge process. The detailed in situ/ex situ characterization demonstrates that the heterostructure of the inner a‐MnBO (x) and surface multicomponent phases endows two energy storage modes (Zn(2+)/H(+) intercalation/deintercalation process and reversible conversion mechanism between the Zn (x) MnO(OH)(2) and Zn(4)SO(4)(OH)(6)·4H(2)O) phases). Therefore, the obtained Zn//a‐MnBO (x) battery exhibits a high specific capacity of 360.4 mAh g(−1), a high energy density of 484.2 Wh kg(−1), and impressive cycling stability (97.0% capacity retention after 10 000 cycles). This finding on a‐MnBO (x) with a dual‐energy storage mechanism provides new opportunities for developing high‐performance aqueous Zn–Mn batteries.