The Research Based On The Preparation And Electrochemical Performance Of ZnS_1-x Shell With Sulfur As Cathode Material For Lithium Sulfur Batteries

The battery help device to obtain energy,with the development of scientific and technological products,the requirements for it are increasingly high,including the current application in electric vehicles and continuous upgrading of mobile electronic devices such as smart phones and wearable devices,which rely on the improvement of the battery to a large extent.At present,as a research hotspot,lithium-sulfur battery may become the leading technology of the next generation battery,which not only has excellent performance,but also has abundant raw materials and is environmentally friendly.But there are still several key issues to be solved before application.At present,the research of lithium-sulfur battery focuses on the optimization of anode and anode materials and the preparation of electrolyte.This paper focuses on the cathode materials of lithium-sulfur batteries.In order to solve the problems of poor conductivity,volume expansion and shuttle effect,we propose an empty shell structure material of ZnS_1-X as the substrate material for carrying active substance sulfur,so as to improve the performance of lithium-sulfur batteries.(1)In this paper,the rod-like precursors of Zn O were firstly obtained by ultrasonic and hydrothermal method,and then the surface of the precursors was sulfurized by sodium sulfide nine water to obtain Zn O@ZnS.After that,the central Zn O was washed away by Na OH solution and sintered at high temperature to obtain ZnS_1-X,and finally the positive electrode composite was obtained by sulfur-enrichment by melting method.The composite material was characterized by SEM,XRD,XPS and other methods,and the electrochemical performance was tested after assembling it into button battery.Finally,the ZnS_1-X adsorption test was conducted.At the current density of 0.2C,the rod-shaped ZnS_1-X/S composite has a specific discharge capacity of 1123m Ah·g^-1 in the first cycle,and can still maintain a reversible capacity of 778m Ah·g^-1 after 200 cycles,showing excellent electrochemical performance,which is also better than the performance of other control groups.The research shows that the rod-shaped hollow shell Zns1-x material can improve the electrical conductivity and adsorption,and has catalytic properties,which can inhibit the shuttle effect in the process of charge and discharge.(2)Then,the spherical and flower-shaped empty shell ZnS_1-X materials were prepared by high temperature stirring and hydrothermal method,and the precursor Zn O was also sent to Zn O@ZnS to prepare the empty shell structure of ZnS_1-X.The microstructure characterization and electrochemical performance test were also carried out.Compared with the control group,the spherical shell material and the flower-shaped shell material still showed the superior performance,but the performance decreased compared with the rod-shaped shell material.At 0.2C current density,the discharge specific capacities of spherical and flower-shaped ZnS_1-X batteries loaded with sulfur elemental materials are 925m Ah·g^-1 and 813 m Ah·g^-1,respectively.After 200 cycles,the reversible capacities of 642 m Ah·g^-1 and 630 m Ah·g^-1 are maintained,respectively.Through longitudinal and horizontal comparison,the hollow shell structure has obvious performance advantages over pure sulfur material and solid structure,and the rod-shaped hollow shell structure also performs better than the spherical and flower-shaped hollow shell structure.