Study On The Supercapacitive Performance Of Cobalt-based Bimetallic Sulfides Derived From ZIF

In recent years,supercapacitors have made great progress.Their high power density and stable cycle performance make them of great research value.In order to improve the performance of supercapacitors,the development of electrode materials with excellent performance is the focus of research.Because transition metal chalcogenide compounds usually have the advantages of flexible structure,abundant electrochemical active sites,high theoretical specific capacitance and electrical conductivity,they have become the research hotspot of supercapacitor electrode materials.Metal-organic framework materials?MOFs?are porous network structure materials formed by transition metal ions as the center and combined with organic ligands through coordination bonds.Its rich pore structure and large specific surface area are conducive to improving the electrochemical performance of electrode materials.In this paper,a series of bimetallic chalcogenide compounds were synthesized through hydrothermal and calcination processes using Co-ZIF-L as a template in MOF materials.And studied the"composition-performance relationship"between its structural morphology and electrochemical performance,the specific work is as follows:1.By adjusting and determining the optimal molar ratio of cobalt nitrate and2-methylimidazole,a sheet-shaped Co-ZIF-L array was successfully prepared on a carbon cloth substrate.After annealing and hydrothermal treatment,Co₃S₄/MoS₂/CC composite material with uniform vertical growth was obtained.Electrochemical tests found that the Co₃S₄/MoS₂/CC composite material after vulcanization has better electrochemical performance than the Co₃O₄ monomer supported on carbon cloth.When the current density is 1 A·g^-1,the specific capacitance of Co₃S₄/MoS₂/CC composite material can reach 805.7 F·g^-1;6000 cycles of charge and discharge tests are performed at a current density of 10 A·g^-1.Its specific capacitance still maintains91.2%of the initial value,showing good structural stability and cycle life.2.Co₃S₄/MnS/CFP composite materials were obtained by using carbon fiber paper as a substrate and growing a Co-ZIF-L array,and undergoing ion etching and vulcanization reaction.The material is evenly distributed on the carbon fiber paper in a porous network structure,and the morphology gradually collapses with the increased of vulcanization degree.The electrochemical tests show that Co₃S₄/MnS/CFP composite materials have good electrochemical properties.At a current density of 1 A·g^-1,it has a specific capacitance of 132.6 F·g^-1;and its capacity remains at 77.2%after 6000 charge and discharge cycles.3.In the case of no substrate,Co-ZIF-L powder was prepared.NiCo₂S₄ bimetallic sulfide was prepared after nickel ion etching,vulcanization reaction and annealing treatment.Morphological characterization revealed that NiCo₂S₄ was in the form of flakes and flocculent particles were attached to the surface.The electrochemical tests show that NiCo₂S₄ bimetallic sulfide has a specific capacitance of 1141.8 F·g^-1 at a current density of 1 A·g^-1;the capacity remains at 65.5%after 6000 charge and discharge cycles,which displayed good rate performance and cycle life.