Preparation And Capacitance Performance Of Composite Material Loaded With Metal Sulfide On Three-dimensional Substrate

There is an increasingly urgent need to study high-performance energy storage equipment to cope with the ever-expanding scale of renewable clean energy.Supercapacitors are expected to become the best energy storage devices due to their excellent performance and low cost.Electrode materials have been extensively studied as a key part of supercapacitors.The three-dimensional structure of the material can provide a high specific surface area,abundant active sites,and better mechanical stability.These excellent characteristics can provide an important guarantee for the preparation of supercapacitor electrode materials with excellent performance.Metal sulfide has excellent characteristics of low cost,high theoretical specific capacitance and high conductivity,but its actual specific capacitance is not high.By combining the two materials,it is expected that a composite material with a high specific capacitance can be obtained.In this paper,NiCo₂S₄ was loaded on three-dimensional graphene by hydrothermal method,and the preparation conditions were explored.Through the characterization and testing of the composite material,the optimal preparation conditions were determined,that is,the ratio of nickel to cobalt was 0.5,thiourea was used as the sulfur source,and the reaction kettle was hydrothermally heated at a temperature of 180? for 16 h.In the samples prepared by this method,it can be seen that NiCo₂S₄ particles with a diameter of 50 nm are loaded on the graphene sheet layer,which has a specific capacitance of 1253.8 F g-1,and it still has a capacitance retention rate of 85%at 10 A g-1.After 1000 charge-discharge cycles,it still has a capacitance retention rate of 82.4%and a coulombic efficiency of 99%.In addition,NiCo₂S₄ was deposited electrochemically on the foamed nickel substrate,and the influence of the number of deposition cycles on it was explored.Characterization and test results show that when the number of deposition cycles is 5,the prepared electrode has the best performance.It has a specific capacitance of 2244.8 F g-1,and at 10 A g-1,it still has a specific capacitance of 1410.1 F g-1.After 1000 cycles of charging and discharging,it still has a capacitance retention rate of 66% and a coulombic efficiency of 99%.