Preparation, Modification And Electrochemical Performance Of SnO₂-MnSn(OH)₆ Composite Lithium Ion Battery Anode Material

In recent years,as people's demand for energy has become more urgent and their dependence on energy has become more serious,the development of electrochemical energy has become an important way for people to solve energy problems.Among electrochemical energy sources,lithium-ion batteries are light and have high energy density.With stable performance,it has become a popular choice for portable energy storage equipment and new energy vehicles.Negative electrode material,as an important part in affecting the performance of lithium-ion batteries,is an important breakthrough to improve battery capacity.Sn and Mn are two very promising anode materials for lithium-ion batteries.They have attracted more and more attention because of their high specific capacity,moderate operating voltage,economical price,and abundant sources.Although they have a high theoretical capacity,the volume effect is obvious during the charging and discharging process of lithium-ion batteries,which will cause changes in the material structure and may cause separation of the electrode material from the current collector,affect the transfer of lithium ions and electrons,and reduce battery capacity And battery cycle life.This article uses Sn and Mn to synthesize SnO₂-MnSn?OH?₆ composite materials by hydrothermal method,and doped with CNTs and graphene to modify and characterize,test and analyze the structure and electrochemical performance of the materials.It mainly includes the following:1. Synthesize SnO₂-MnSn?OH?₆ composites.By controlling the content of Sn and Mn,different ratios of Sn-Mn composites were prepared.The characterization test of the material found that the SnO₂-MnSn?OH?₆composite with a Sn-Mn ratio of 8:2 had the best electrochemical performance;Chemical properties are slightly worse.2. SnO₂-MnSn?OH?₆ composites were doped with CNTs at 8:2 and 4:6,respectively.SnO₂-MnSn?OH?₆-CNTs ternary composites with different CNTs content were prepared.The electrochemical performance test shows that the optimal doping amount of CNTs in a composite with a Sn-Mn ratio of 8:2 is 15%;and the optimal doping amount of CNTs in a composite with a ratio of 4:6 is also 15%;Comparing the two,it was found that the composites with the Sn-Mn ratio of 4:6 and the CNTs content of 15%had the best performance.3. The SnO₂-MnSn?OH?₆ composite was doped with graphene to control the graphene content,and different samples were prepared.The morphology and structure of the samples were characterized,and the cycle,magnification,and Testing of impedance,CV,etc.,it was found that the addition of graphene made the cubic structure of MnSn?OH?₆ more regular and uniform;and the electrochemical performance of the sample with graphene content of 50%was the best.