Prepartion And Sodium Storage Properties Of Tin-based Sulfide Composite Materials

Tin-based sulfides stand out among many anode materials due to the high theoretical capacity and abundant resources.However,the tin-based sulfides will inevitably undergo violent and irreversible volume expansion during the cycling process,resulting in rapid electrode pulverization.In addition,the poor conductivity and the slow reaction kinetics of tin-based sulfides lead to a sharp decline in capacity and deterioration in rate performance,which limit its application.Therefore,in order to solve these problems,we prepared tin-based sulfide composites and carried out electrochemical performance tests.The research work are as follows:(1)Precursor was prepared by a simple hydrothermal method and then calcined in argon atmosphere.A novel hollow tube heterostructure Sb2S3@SnS@C composites were successfully prepared.Due to the ingenious design and efficient construction of the Sb2S3@SnS heterostructure,an in-built electric field is generated in the material,which greatly promotes ion difusion and accelerates charge transfer and conformed with the DFT calculations.At the same time,the hollow rod-like structure generated by the evaporation of Sb2S3 greatly increases the reaction area,which also allows space to be reserved for the volume expansion of the material during the cycles.When combined with carbon material,the volume change can be further alleviated,and Sb2S3@SnS@C composites show good electrochemical performance.It delivered a high capacity of 442 mA h g-1 after 200 cycles at 1 A g-1 and excellent rate capacity of 448 mA h g-1 at 5A g-1.Besides,a capacity of 200 mA h g-1 could be detected for superior cycling performance after 1300 cycles at 5.0 A g-1.(2)The flower-like SnS2 was prepared by hydrothermal method,and the SnS2@SnO2 heterojunction was obtained by partial oxidation on this substrate.Similarly,the method of coating dopamine was used to compound SnS2@SnO2 with carbon materials,and finally the flower-like SnS2@SnO2@C composites was obtained.The successful synthesis of SnS2@SnO2@C was confirmed by a series of characterization methods.Due to the presence of the heterojunction structure and the buffer volume expansion of the carbon layer,the SnS2@SnO2@C composites exhibit excellent electrochemical performance.Besides,a capacity of 197 mA h g-1 could be detected for cycling performance after 350 cycles at 1 A g-1...