| In order to cope with the energy crisis,it is of great significance to develop a secondary battery that is efficient and convenient and suitable for large-scale energy storage.Due to the continuous increase in the price of lithium and the increasing shortage of lithium resources,the application and development of lithium-ion batteries in the field of large-scale energy storage are limited.Compared with lithium-ion batteries,sodium and lithium have similar physical and chemical properties,and have natural advantages in resource reserves and costs.Therefore,sodium-ion batteries,as the most promising next-generation batteries,can be combined with other energy storage systems in the future.Building a new energy system together has become one of the research hotspots.In this paper,SnO2 recovered from tin mud is used as the base material and doped and modified to obtain the negative electrode material of sodium ion battery.Explore the influence of different mass ratios on the electrochemical performance of ZnS/C-SnO2(tin mud)materials;The influence of the main impurity components of tin mud on the electrochemical performance of ZnS/C-SnO2 material and the doping mechanism are analyzed.In addition,the influence of different sulfur sources,different amounts of carbon doping and different calcination temperatures on the electrochemical performance of SnS/C materials was futher studied;preliminary explorations were made on SnS/SnO2/C composite materials.Combined with SEM,TEM,XRD and electrochemical testing techniques,the electrochemical performance of the prepared various anode materials was analyzed in depth.Draw the following main conclusions:(1)The electrochemical properties of ZnS/C and ZnS/C-SnO2(tin mud)composite materials were studied,and the results showed that the ZnS/C-SnO2(tin mud)composite material has better electrochemical performance.At a current density of 50 mA·g-1,the first coulombic efficiencies are 51.3%and 59.13%,respectively.The ZnS/C-SnO2 composite material has a high first-time coulombic efficiency,indicating that the tin mud material can improve the first-time coulombic efficiency and cycle stability of electrode materials.(2)The influence of different mass ratios on the electrochemical performance of ZnS/C-SnO2(tin mud)composites was studied.The results show that the composites with a mass ratio of 3:1 has better electrochemical performance.At a current density of 100 mA·g-1,the first charging specific capacity of this material is 431.5 mAh·g-1,and it has a charge capacity retention rate of 69.7%after 100 cycles.At various current densities,the samples prepared with a mass ratio of 3:1 ZnS/C-SnO2 composites showed better specific capacity.(3)The influence of different BaSO4 doping amounts on the electrochemical performance of ZnS/C-SnO2-BaSO4 composites was studied,and the results showed that the composites with 5%doping amount has better electrochemical performance.At a current density of 50 mA·g-1,the capacity remains at 301 mAh·g-1/305.6 mAh·g-1 after 50 cycles,and the first coulombic efficiency is 62.32%.Compared with undoped materials,the cycle performance is significantly improved.At various current densities,the ZnS/C-SnO2-BaSO4 composite material doped with BaSO4 5%showed better specific capacity.(4)The mechanism of improving the cyclic properties of BaSO4 doped materials was studied.Results show that the BaSO4 doping through to a certain extent,inhibit and buffer Na-Sn alloy in the process of charging and discharging volume change,makes the volume change of electrode material tends to be stable,and the charge transfer resistance materials Ret is far less than not doping,The ionic mobility of sodium ions in the electrode material is increased,and the cyclic stability of the electrode material is improved.(5)The effects of different sulfur sources,different carbon content and different calcination temperature on the structure and electrochemical properties of SnS/C composites were studied.The results show that the SnS/C composites prepared with thiourea(H2NCSNH2)as sulfur source,carbon content of 50%and calcination temperature of 700℃ have higher charging-discharge specific capacity.The SnS/C composites prepared under these conditions have a charge-discharge specific capacity of 543.2 mAh·g-1/857.5 mAh·g-1 and a coulomb efficiency of 63.35%for the first time.The capacity remained at 310.3 mAh·g-1/315.2 mAh·g-1 after 50 cycles at a current density of 50 mA·g-1.(6)The SnS/SnO2/C composites prepared from tin slime were studied.At the current density of 50 mA·g-1,the first charge-discharge specific capacity was 510.6 mAh·g-1/829.4 mAh·g-1,and the first coulomb efficiency was 61.6%.After 50 cycles,the charge-discharge specific capacity is 457 mAh·g-1,with a charge capacity retention rate of 89.5%,and the cycle stability is significantly improved compared with SnS/C composites. |
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