Application of cobalt-modified irregular cubic block–shaped MnCO₃@Mn₃N₂@Mn₂O₃ composite cathode material in aqueous zinc-ion batteries

Manganese-based aqueous zinc-ion batteries have attracted significant attention and research in the academic community due to their good cycling stability and high capacity. It has been found that manganese-based aqueous zinc-ion batteries exhibit excellent safety in energy storage applications. In this study, cobalt-modified manganese-based composites were synthesized via the hydrothermal method. The optimal synthesis route was achieved by optimizing the amount of cobalt, hydrothermal conditions, and calcination conditions. The manganese-based material prepared under the optimal conditions exhibited maximum capacity of 425.35 mAh/g at current density of 50 mA/g, and capacity of 296.05 mAh/g at current density of 100 mA/g. The SEM characterization revealed that the material had a microstructure of cubic blocks with surface protrusions, featuring triangular and trapezoidal cross-sections of the protrusions. The EDS analysis indicated that the main components on the material surface were Mn, C, and O element. The infrared and Raman spectroscopy confirmed the presence of Mn–O bonds and carbonate structures in the material. After refinement and quantitative analysis, the XRD analysis identified the main components of the composite material as MnCO₃, Mn₃N₂, and Mn₂O₃, with a small amount of cobalt oxide present.