Study On The Controllable Synthesis Of Ternary Metal Sulfide NiCo₂S₄ And Its Supercapacitance Properties

With the rapid development of global economy,non-renewable resource have been consumed at a fast speed.In order to improve the living standard and induce the development of economic,scientific and technological level,the search for clean and efficient renewable resources has become an unavoidable topic in the scientific field.In recent years,lithium batteries,fuel cells and supercapacitors as energy storage materials have been the focus of research.Electrode materials are the most important part of energy storage equipments,which directly determine the performance of energy storage equipments.As a battery electrode material,from the perspective of performance,it needs to have better chemical stability and good conductivity.From the perspective of actual production,it needs to have lower production cost and simpler production process.Among many materials,the ternary metal sulfide NiCo2S4 has good conductivity because of its abundant number of electrons and efficient electron transfer rates.According to previous studies,most of the synthesis methods of NiCo2S4 are hydrothermal method and template method,and it is difficult to obtain both convenient synthesis methods and products with regular morphology.Therefore,this paper will focus on the preparation of ternary metal sulfide NiCo2S4 nanoparticles with regular morphology by a more convenient synthesis method.Moreover,the sulfide was compounded with 3d carbon nanotubes to improve the specific surface area and active sites of the products,and to improve the conductivity of the complex.The application of these materials in the field of supercapacitors has been studied in depth.The main research results are as follows:1.A simple one-step solvent thermal method was designed to prepare monodisperse MCo2S4 nanoparticles and the properties of the nanoparticle products as supercapacitor electrode materials were explored.In this experiment,nickel acetylacetone and cobalt acetylacetone were used as the nickel source and cobalt source respectively.Dibenzyl disulfide was used as the sulfur source.And the mixed solution of octadecene and oleamine was fully mixed.Compared with previous research results,products with both good monodispersity can have a larger specific surface area,also have more excellent performance of capacitance.With the current density of 1 A/g,capacitance can reach 1594.8 F/g,and under high current density of 20 A/g after 3000 cycles,electrode still can keep 70%of the original content of capacitance.Compared with the same type of similar products,its capacitance performance is pretty good.2.In order to further improve the performance of NiCo2S4 nanoparticles as capacitor electrodes,the nanoparticles were combined with three-dimensional carbon nanotubes with pleated internal structures.Three-dimensional carbon nanotubes(NPC),due to their special carbon frame structure,can provide more attachment points for nanoparticles and improve the specific surface area of materials.In addition,the electrical conductivity of the composite can be improved.The composite also showed good capacitance performance as expected:the capacitance reached 2138.8 F/g at the current density of 1 A/g,and maintained 76%of the original capacitance after 3000 cycles at the current density of 20 A/g.3.Exploring the use of atomic layer deposition(ALD)method to attach TiO2 to the surface of NiCoP nanoparticles with excellent monodispersity.In this way,the problem that the substances synthesized in the oil phase are difficult to compound with TiO2 can be well solved,and the phenomenon that NiCoP is easy to agglomerate can also be improved.Compared with the pure phase NiCoP nanoparticles,the composite exhibits better superelectric and cyclic properties.