Research On Preparation And Electrochemical Properties Of Copper Oxide/C Composites

The redox process of metal oxides can produce higher pseudo capacitance effect,which has become a research hotspot for supercapacitor electrode materials in recent years.Metal oxide electrode materials such as yttrium oxide,nickel oxide and cobalt oxide have high specific capacity,but they also have a lot of problems such as high cost of materials,environmental pollution and so on.CuO has become a choice because of its low cost and no pollution in recent years.However,it still has the disadvantages of low specific capacity and poor cycle stability.In this dissertation,we use graphene and carbon nanotubes as substrates to load CuO to improve the specific surface area and active material utilization,and improve the specific capacity and cycle stability.The main content of the paper are as follows:(1)Copper oxide/multilayered graphene(CuO/MLG)composites were prepared by hydrothermal synthesis.The influence of reactant addition and temperature on the microstructure of composite was studied,and the electrochemical performance was also tested.The results show that spherical particles of CuO are distributed on the surface of multilayered graphene,and when the hydrothermal temperature is 80?,there are rod-like substances on the surface of graphene.With the amount of reactants increased and the temperature increased,the size of the CuO particles loaded on the surface gradually becomes larger.The electrochemical test results showed that the composite materials had the highest specific capacity when adding 100 mg copper acetate at hydrothermal temperature of 120°C and reached 184F/g at a current density of 1A/g.And when the particle size of CuO is smaller,the composites has better cycling stability.The composite materials with size of CuO less than 20 nm were prepared at hydrothermal temperature of 70°C,and after 6000 constant current charging and discharging the specific capacity can be kept unchanged.(2)Copper oxide/carbon nanotube(CuO/CNTs)composites were prepared by hydrothermal synthesis.The influence of reactant addition on the microstructure of composite was studied,and the electrochemical performance was also tested.The results show that CuO attached to carbon nanotubes with uniform distribution,and the particle size is between 100 and 300 nm.The electrochemical test results showed that the composite materials had the highest specific capacity when adding 100 mg copper acetate and reached 212F/g at a current density of 1A/g.And when adding50 mg copper acetate,the composite has the best cycling stability.After 7000 constant current charge and discharge,the specific capacity retention rate is97.7%.It can be concluded that graphene and carbon nanotubes as substrates for loading CuO has many advantages.It increases the contact area between the active substances and the electrolytes,so the specific capacity is increased.It provides buffer space for the volume deformation of active substances during charging and discharging,so the cycling stability is also improved.The composites have excellent electrochemical properties.