Preparation And Superelectric Properties Of Cobalt-nickel ZIF-67 Composite Electrodes

The energy shortage crisis has given supercapacitors a major mission.The supercapacitors have raised concern in the area of energy storage,which have many satisfactory characteristics such as high specific capacitance.The study of electrode materials has become a favorite topic.Because it has excellent specific capacitance and energy/power density.The capital task of the paper is to prepare Co₂Ni Se₄,Co₂Ni O₄/g-C₃N₄(Ni/Co-CN),Co Ni₂S₄ based on cobalt-nickel ZIF-67 material.as a supercapacitor electrode material.The properties of the three materials were tested at the same time.Here,cobalt-nickel ZIF-67 is selected as the precursor,and Co₂Ni Se₄ is prepared by calcination method by mixing with a certain proportion of Se powder.The prepared Co₂Ni Se₄ inherits the outline of the precursor and has a hollow internal structure.In this paper,the affects of unequal selenization ratios on the scale of Co₂Ni Se₄ materials are investigated.Appropriate Se powder ratio not only affects the morphology of Co₂Ni Se₄.And it has a significant effect on the electrochemical performance.When the ratio of selenization is 1:1,the Co₂Ni Se₄(1)material shows a specific capacitance as high as1479.7 F g^-1 at 1 A g^-1.Co₂Ni Se₄(1)//AC ASC can provide an energy density of 35.79Wh kg^-1.A new electrode material is synthesized using a simple solvothermal method to synthesize a Co₂Ni O₄ cube composite derived from ZIF-67 decorated with flower-like g-C₃N₄(CN)nanosheets.The Ni/Co-5%CN sample is found to have a higher BET specific surface area of 135.4 m~2 g^-1.When the adding quantity of CN is 5%,Ni/Co-5%CN has a better specific capacitance of 1701 F g^-1 at 1 A g^-1.In addition,under asymmetric conditions,Ni/Co-5%CN//AC ACS can have an ideal energy density of 51.38 Wh kg^-1.After 5000 cycles,it has a capacitance retention rate of nearly 91.5%.It shows that Ni/Co-CN has great potential in constructing low-cost,safe and high-performance supercapacitors.The Co Ni₂S₄ hollow polyhedrons are prepared by using cobalt-nickel ZIF-67 as a precursor and adding appropriate amount of thioacetamide for sulfurization.As an electrode material of supercapacitors,hollow Co Ni₂S₄ cubes show a high specific capacitance of 2450 F g^-1(at 1 A g^-1).In addition,studies have also been carried out in an asymmetric supercapacitor(ASC)system based on Co Ni₂S₄ hollow cubes,which has a high energy density of 62.19 Wh kg^-1.And it has stable across multiple cycle tests.The synthesis method is oversimplified.And the electrochemical performance is excellent,showing that it has certain prospects in supercapacitor electrode materials.