Phase-Transformation-Activated MnCO3 as Cathode Material of Aqueous Zinc-Ion Batteries

Abstract

The intrinsic high safety of rechargeable aqueous batteries makes them particularly advantageous in the field of large-scale energy storage. Among them, rechargeable Zn–Mn batteries with high energy density, low cost, high discharge voltage, and nontoxicity have been considered as one of the most promising aqueous battery systems. However, exiting research on manganese-based cathode materials mainly focuses on diverse manganese oxides analogs, while reports on other promising manganese-based analogs with high performance are still limited. Herein, we report a MnCO3 cathode material, which can be manufactured on a large scale by a facile coprecipitation method. Interestingly, the MnCO3 can spontaneously be converted into MnO2 material during the charging process. The Zn–MnCO3 battery delivers a highly specific capacity (280 mAh g−1) even at the high current density of 50 mA g−1. It is also noteworthy that the battery with a high loading mass (7.2 mg cm−2) exhibits good reversibility of charge–discharge for 2000 cycles, showing a competitive cycling stability in aqueous systems.

Crystalline MnCO3@Amorphous MnOx Composite as Cathode Material for High-Performance Aqueous Zinc-Ion Batteries

“…45 Moreover, the characteristic vibrational peak of Zn−O appears at 300−400 cm −1 when discharged to 0.8 V, which disappeared after subsequent charging, further indicating the successful intercalation of Zn 2+ and the good reversibility of the MnCO 3 @A-MnO x electrode. 76 Based on the above analysis and related literature reports, 39,77,78 it can be concluded that during the first discharge process, H + is intercalated into the MnCO 3 @A-MnO x to form hydroxymanganese oxide first, and it is reasonable to report in the literature that although H + is intercalated in the intercalation layer, the characteristic peaks of hydroxymanganese oxide can hardly be observed, 59,62 and the subsequent reactions occur as a result of an increase in OH − in the system. It is worth mentioning that for the MnCO 3 electrode, there is no capacity at the first discharge, followed by a long plateau in its charging curve at the first charge process, as shown in Figure S10.…”