Effect of Magnesium Site Doping on Electrochemical Properties of Mg-Mn Composite Materials and Application of Carpet-Like Sheets Composite Formed by Cr Doping in Aqueous Zinc-Ion Batteries

Abstract

Manganese-based compounds have very stable electrochemical properties when applied to aqueous zinc-ion battery. However, it is easy to dissolve manganese in the process of charge and discharge, leading to the collapse of the cathode material structure. In our study, the composite materials of manganese carbonate and magnesium carbonate were synthesized by hydrothermal method, and its properties were optimized by doping modification. According to the electrochemical test, the electrochemical performance of the material synthesized by doping 5% Cr element is relatively stable, the capacity rises to 212.01 mAh/g. Scanning electron microscopy showed that in addition to the cube shape, there are also carpet-like sheets made of nano-sized petal-like structures joined together, which greatly increases the specific surface area of the material. Energy-dispersive spectroscopy and X-ray photoelectron spectroscopy tests confirmed that the types and valence states of elements in the composites were consistent with those in manganese carbonate and magnesium carbonate. It can also be seen from the infrared and Raman tests that the functional groups in the synthesized material correspond to the molecular formula. No obvious impurity peaks are seen in the X-ray diffraction pattern, indicating that the material is mainly composed of manganese carbonate and magnesium carbonate.