Preparation of magnesium carbonate and manganese carbonate composite materials doped at manganese site by hydrothermal method and study of Co doping effect

Aqueous zinc ion battery is considered the most likely to replace lithium ion battery due to its stable electrochemical performance and economic environmental protection. Manganese-based battery material is one of the most potential aqueous zinc ion battery materials. Aiming at the problem of manganese dissolution easily occurring in manganese based materials, metal doping modification research was carried out on the manganese site of materials, and MgCO3@2Mn1-yXyCO3 material was synthesized and assembled into zinc ion batteries for testing. Through the analysis and comparison of the electrochemical test results, it is found that the comprehensive properties of MgCO3@2Mn0.99Co0.01CO3 materials are better. The material has a power capacity of 345.85 mAh/g at 50 mA/g current density. Two main morphologies can be observed in SEM images, namely, the regular cube structure with triangular pyramid and the sheet structure formed by the accumulation of nanoscale small cubes. The EDS scanning and XPS testing on these structures confirmed that the types and valence states of elements contained in these structures corresponded to manganese carbonate and magnesium carbonate, and were evenly distributed. The infrared test and Raman tests also confirm that the functional groups in MgCO3@2Mn0.99Co0.01CO3 material are consistent with the molecular formula. In the XRD analysis of MgCO3@2Mn0.99Co0.01CO3 material, no obvious impurity peak was found, indicating that the purity of the composite material is high.