Phase transformation mechanism of MnCO(3) as cathode materials for aqueous zinc-ion batteries

Aqueous rechargeable zinc-ion batteries (ZIBs) have been given more and more attention because of their high specific capacity, high safety, and low cost. The reasonable design of Mn-based cathode materials is an effective way to improve the performance of ZIBs. Herein, a square block MnCO(3) electrode material is synthesized on the surface of carbon cloth by a one-step hydrothermal method. The phase transition of MnCO(3) was accompanied by the continuous increase of specific capacity, and finally maintained good cycle stability in the charge–discharge process. The maximum specific capacity of MnCO(3) electrode material can reach 83.62 mAh g(−1) at 1 A g(−1). The retention rate of the capacity can reach 85.24% after 1,500 cycles compared with the stable capacity (the capacity is 61.44 mAh g(−1) under the 270th cycle). Ex situ characterization indicates that the initial MnCO(3) gradually transformed into MnO(2) accompanied by the embedding and stripping of H(+) and Zn(2+) in charge and discharge. When MnCO(3) is no longer transformed into MnO(2), the cycle tends to be stable. The phase transformation of MnCO(3) could provide a new research idea for improving the performance of electrode materials for energy devices.