Preparation And Electrochemical Performance Of Self-standing MCo₂S₄?M=Mn,Ni?

With the excessive development and utilization of energy,mankind has begun to face an energy crisis,so the development and use of stable new energy sources is imminent.In view of this,researchers are studying electrode materials with high capacity.As a high-efficiency energy storage device,supercapacitors are widely used in the fields of electronics,aviation and communications.The abundant natural resource reserves and low cost of sodium metal have made the practical application of sodium ion batteries in electric vehicles begin to become a hotspot.MnCo₂S₄?MCS?and NiCo₂S₄?NCS?have attracted the attention of researchers at home and abroad because of their unique nanostructures,good redox properties,low cost,and simple preparation methods.However,the synthesis process of MCS and NCS is not uniform,its own chemical properties are not clear,and the current application field needs to be further expanded.In this paper,foamed nickel was used as a substrate,and MCS and NCS were prepared by hydrothermal method,and applied to supercapacitors and sodium ion batteries.Then,each characterization and electrochemical performance research and analysis were carried out,and electrode materials with better electrochemical performance were expected..The main research contents of this article are as follows:?1?Using Mn?NO₃?₂·4H₂O?Ni?NO₃?₂·6H₂O?and Co?NO₃?₂·6H₂O as raw materials,thiourea as a mineralizer,and foamed nickel as a substrate,the self-standing MCS and NCS are obtained by a one-step hydrothermal method at high temperature and applied to supercapacitors.The effects of hydrothermal reaction time and metal salt concentration on the morphology of nanomaterials were systematically investigated.The results show that when the reaction time is 5h,with the increase of the metal salt concentration,the morphology of the product changes from tubular to lamellar structure to petal-like structure;NCS with the increase of the metal salt concentration,the product morphology changes from mixed structures?cubic cubes,nanotubes,sheets?to three-dimensional network structures that are cross-linked to continuous petal-like structures.When the current density is 10A g^-1,the specific capacitance of 5MCS-2 with tubular structure and 5NCS-2 with mixed structure can reach 2667F g^-1 and 1623F g^-1,respectively.In addition,5MCS-2 has good cycle stability,and the capacitance retention rate after 1800 cycles is 68%.These excellent electrochemical properties can be attributed to the higher effective area and higher conductivity of the sample.Therefore,MCS and NCS have great development prospects as supercapacitor electrode materials.?2?A one-step hydrothermal method was used to hydrothermally synthesize MCS on nickel foam and used it as the negative electrode material of sodium ion batteries.By regulating the hydrothermal reaction temperature and the metal salt concentration,the anode material of sodium ion battery with better performance is obtained.The results show that when the reaction temperature is the same?180??,the metal salt concentration is adjusted.When the Ni/Co ratio is 10:6,the electrochemical performance of MCS-6 is better.After the rate test shows that MCS-6 has a smaller specific capacity loss after charge and discharge tests at different current densities.When the metal salt concentration is the same?10:10?,adjust the hydrothermal reaction temperature.When the temperature is 120?,the performance of the MCS-120 sample is better.At a larger current density of 500 mA g^-1,the specific discharge capacity at the first cycle showed 1129.4 mAh g^-1.After 40 cycles,the capacity of the sodium battery remained at 255 mAh g^-1,showing a higher ratio capacity.