Preparation And Properties Of Nickel-based Composite As Electrode Materials For Supercapacitors

Supercapacitor has the advantages of short charging time,high specific capacity and energy density,long cycle life and environmental friendliness.It is an important branch of advanced energy storage technology,and has broad application prospects in power system,high frequency energy storage,auxiliary power supply for vehicles and rail transit.Electrode material is the key to the performance of supercapacitors.Among the various electrode materials currently known,Ni oxides and hydroxides not only have lower cost,but also have unique redox characteristics and higher theoretical specific capacitance,so they are considered a promising pseudocapacitance electrode material.However,Ni O electrode materials have the problems of low electronic conductivity,poor cycle stability and rate characteristics.In order to solve these problems,researchers have proposed the improvement scheme of preparing nanostructured Ni O and combining Ni O with other conductive materials.In this paper,nickel-based composite materials are the main research object.By adjusting the proportion of the dopant ions,a complexing agent to adjust the morphology and auxiliary methods such as high-temperature calcination,a composite material with uniform morphology,small size and regular structure is obtained as a self-supporting electrode,and its research Charge storage characteristics.Based on this,this article conducts the following research:1.In this paper,a one-step hydrothermal method is used to prepare a Co-doped Ni(OH)₂electrode on a foamed nickel substrate.The composite material is covered by Co-Ni(OH)₂nanoflowers on the foamed nickel framework.Electrochemical test results show that the self-supporting,non-bonding Co-Ni(OH)₂electrode prepared by this method has good electrochemical performance(a specific capacity of 2765.24 F·g^-1at 4 m A cm^-2),much higher than the specific capacity of other similar electrode materials.Assembled with AC to form a aqueous hybrid supercapacitor,it exhibits a high energy density of 44.99Wh kg^-1(power density of 485.71 W kg^-1),and a current density of 30 m A cm^-2after 3000 cycles with 86.12%specific capacity retention rate.2.A two-step method of hydrothermal reaction and calcination was used to synthesize Ni Co₂O₄nanoneedle arrays with well-adhered small particles self-assembled on foam nickel.The electrode has excellent electrochemical performance in the three-electrode electrochemical test.The specific capacity reaches 2.8 F cm^-2(1311.870 F·g^-1)at 2 m A cm^-2,and the specific capacity retention rate is 171.90%after 4000 cycles of continuous charging and discharging.The assembled Ni Co₂O₄/NF//AC hybrid supercapacitor also shows good energy storage performance and application prospects.The capacitance retention rate is85.19%after 5000 cycles,and the high power density of 850 W kg^-1is achieved at an energy density of 32.73Wh kg^-1.