Preparation And Electrochemical Properties Of Bimetallic Sulfide Electrode Materials

As a new type of electrochemical energy storage device,supercapacitor has attracted much attention because of its high power density,excellent cycle performance and fast charge and discharge capability.One of the cores of supercapacitors is the electrode material.The quality of the electrode material directly determines the performance of the capacitor device.Among many materials,bimetallic sulfide is considered to have its unique structure and excellent electrochemical performance.Great potential electrode material.In this paper,FeCo₂S₄/CF,NiCo₂S₄/CF,NiCo₂S₄@Ni?OH?₂/CF were successfully prepared by compounding bimetallic sulfide and carbon cloth?CF?materials and hydroxides,and the process parameters were discussed.The effects of chemical properties,and assembly of supercapacitor devices,test the overall electrochemical performance.1.FeCo₂S₄/CF composite electrode material was successfully prepared by simple hydrothermal method.FeCo2S4 was successfully grown on the surface of CF with CF as the substrate.Nano-tubular and turf-like FeCo₂S₄ were prepared by different sulfur sources.When Na₂S·9H₂O is a sulfur source,the nano-tubular FeCo₂S₄ composite grown on carbon cloth has the best electrochemical performance:at a current density of 1 A·g^-1,the specific capacitance can reach 486 F·g^-1.The nano-tube FeCo₂S₄/CF composite material is used as the positive electrode,and the commercial RGO is used as the negative electrode to assemble the asymmetric water-based supercapacitor,and the performance is good.The energy density can reach 32.5 Wh·kg^-1,at the current density of 1 A·g^-1,the corresponding power density is 780 W·kg^-1,and after 5,000cycles,it can still maintain 85.2%of capacity.2.The NiCo₂S₄/CF electrode material was successfully prepared by a simple"two-step"hydrothermal method.NiCo₂S₄ was directly grown on the base material carbon cloth and used as an electrode without added binder.On this basis,we studied the influence of ammonium fluoride on the morphology and electrochemical properties of NiCo₂S₄ electrode materials,and carried out the phase structure characterization and electrochemical performance test of the samples to explore the optimal preparation process.At the current density of 1 A·g^-1,the nanorod NiCo₂S₄/CF electrode material exhibits the best performance,the specific capacitance can reach 884 F·g^-1,and the specific capacitance of the chrysanthemum NiCo₂S₄/CF is 630 F·g^-1,seaweed-like NiCo₂S₄/CF is the worst 408 F·g^-1.3.NiCo₂S₄@Ni?OH?₂/CF composite electrode material with core-shell structure was prepared by synthesizing Ni?OH?₂ on the surface of NiCo₂S₄ nanorods by constant voltage deposition.The effects of electrodeposition time on the microscopic morphology and electrochemical properties of NiCo₂S₄@Ni?OH?₂/CF electrode materials were investigated.The performance of NiCo₂S₄@Ni?OH?₂/CF was best when electrodeposited for 6 min.The specific capacitance of at 1 A g^-1 can reach 1546F·g^-1.NiCo₂S₄@Ni?OH?₂/CF is used as the positive electrode,and AC is the negative electrode assembled asymmetric solid supercapacitor.The energy density can reach20.4 Wh·kg^-1,and the corresponding minimum power density is 850 W·kg^-1.In order to demonstrate the practical application value of the ASC,the LED small bulb was successfully illuminated using two ASCs in series.