Study On The Controllable Preparation Of Nickel/Cobalt-based Sulfide Electrode Materials Using NaCl And Their Energy Storage Performance

Nowadays,with the increasing demand for all kinds of energy,fossil fuels have been in short supply.In this sense,a device with high capacity and high power density is needed to serve future energy storage applications.Usually,in order to meet such performance requirements,it is necessary to first prepare good electrode materials.Therefore,researchers are conducting more and more in-depth research in this field.Nickel/cobalt-based sulfides have a variety of structural types and unique electrochemical activities.In order to improve the utilization rate of materials,people also have a variety of choices in the use of its preparation methods.In this paper,based on the regulation technology of NaCl at the level of electrode material structure,nickel/cobalt-based sulfides were successfully prepared.Through the phase characterization and electrochemical testing of related materials,the application progress of nickel/cobalt-based sulfide electrode materials in the field of energy storage is deeply studied.The specific research content is as follows:（1）NiS₂ nanomaterials with high purity were prepared by the NaCl-assisted less-liquid reaction system.Firstly,without adding any additional solvent,the crystalline water in the reactant is used to directly provide a liquid environment for the reaction,so that the whole reaction can be carried out safely and efficiently in the reaction system with less liquid.In addition,based on the space effect of NaCl solution,cotton-like NiS₂ was synthesized in one step in a confined space.The prepared material is closely connected and has rich active sites,which facilitates the rapid transport of charge.The cotton-like NiS₂ is used as the cathode material in the magnesium ion battery.At the current density of 0.05 A g^-1,the specific capacity of the magnesium ion battery reaches 262.1 mAh g^-1,which has a good application prospect.（2）High purity cauliflower CoS₂ nanomaterials were prepared by NaCl-assisted less-liquid reaction system.The introduction of NaCl improves the uniformity and purity of the microstructure of CoS₂,promotes the exposure of more defect sites in the material,and is conducive to the efficient utilization of active materials.In the application of supercapacitors,the specific capacitance is 265.4 F g^-1 when the current density is 0.5 A g^-1,using CoS₂ as the cathode material and in the three-electrode system;Under the assembled asymmetric two-electrode device,when the current density is 0.5 A g^-1,the specific capacitance reaches 188.1F g^-1.After 10000 cycles of testing,the coulomb efficiency can reach about 90%under the current density of 5 A g^-1.（3）NiS nanosphere electrode material was prepared by low temperature solid phase method assisted by NaCl.In the process of material growth,NaCl acts as a pillar to effectively prevent the nanoflakes from becoming thicker,thus forming NiS nanospheres.In the three-electrode system of the supercapacitor,when the current density is 0.5 A g^-1,the specific capacitance is 390.8 F g^-1;Under the assembled asymmetric two-electrode device,the specific capacitance is 351.6 F g^-1.The participation of NaCl plays a decisive role in the morphology of the product,providing more convenience for the preparation of nanomaterials with diverse morphologies and structures.