Preparation And Electrochemical Performance Of Nickel-based Composites

Supercapacitors,as a new type of green energy storage device,have become a research hotspot because of its fast charge and discharge speed and high power density.However,its low energy density limits its practical application to some extent.Studies have shown that nickel-based materials such as Ni?HCO₃?₂ and Ni?OH?₂ have higher theoretical specific capacitance and energy density,so the development potential is greater.Nonetheless,it has its own defects of poor conductivity,short life,and easy stacking.Therefore,it is important to find a material that can be combined with it to optimize the overall performance.Materials such as copper,copper oxide,and activated carbon are widely used in combination with other materials because of their low cost,high electrical conductivity,and high chemical stability,and are used in the field of capacitors by utilizing synergistic effects and substrates.The resulting composite material has strong electrical conductivity and stability.In this paper,nickel-based functional materials were combined with copper-containing compounds and activated carbon,respectively,and a series of electrochemical properties of the materials were systematically discussed.The main research contents of this paper are:Firstly,copper element was introduced into the crystal lattice of nickel oxide to obtain nickel-copper double-metal oxide.The double-metal oxide was further combined with Ni?HCO₃?₂,which effectively accelerated the charge transfer rate during charge and discharge,and improved the conductivity and stability of the material.In addition,the synergy between nickel and copper was maximized by adjusting the molar ratio between nickel and copper to obtain an optimum composite.The energy density of the asymmetric capacitor device NC-d//AC was as high as 52.9 Wh kg^-1.Secondly,the porous nickel-containing activated carbon prepared by the activation method was used as a substrate to directly grow nickel-cobalt double hydroxide nanosheets to investigate the effect of nitrogen-containing activated carbon on the properties of the material.It was found that the nitrogen-containing activated carbon greatly increased the specific surface area of the material,reduced the stacking of NiCo-DHs,and improved the electrical conductivity and cycle life of the material.The resulting NAC/NiCo-DHs had a high specific capacitance of 1920 F g^-11 at 1 A g^-11 and good cycling stability with 95.54%specific capacitance retained after 1000 cycles.The assembled NAC/NiCo-DHs//AC device exhibited a maximum energy density of 54.8 Wh kg^-1.Finally,Cu/CuO nanoparticles which can be uniformly dispersed in aqueous ethanol solution were obtained by a simple redox method,and then the core-shell Cu/CuO@Ni?OH?₂material was synthesized by a simple solvothermal method.The structure and morphology of the materials were characterized,and the effects of Cu/CuO nanoparticles on the electrochemical properties of Cu/CuO@Ni?OH?₂ materials with core-shell structure were investigated.