Preparation And Properties Of Composite Electrode Material Based On Carbon Nanotubes

Carbon nanotubes（CNTs）have become a hot spot in the field of supercapacitor electrode materials due to their excellent physical and chemical properties.However,CNTs have low specific capacitance and cannot meet the energy density requirements when used alone as electrode.Based on this,CNTs are used as conductive substrate to compound with other materials,and three kinds of high-performance composite materials with three-dimensional（3D）conductive network structure are designed.Using carboxylated carbon nanotubes/zeolite imidazolate framework-67（C-CNTs/ZIF-67）as the precursor,carboxylated carbon nanotubes/nickel cobalt layered double hydroxide（C-CNTs/NiCo-LDH）composites with 3D hollow nanocage structure are prepared by thermal ion exchange method.When the nickel source is 120mg,C-CNTs/NiCo-LDH-120 exhibits a high specific surface area(137.69m²·g^-1)and a specific capacitance up to 1505.4F·g^-1.The supercapacitor composed of this electrode material shows a high energy density of 30.38Wh·kg^-1at the power density of 750W·kg^-1.C-CNTs/ZIF-67 is used as the precursor again.C-CNTs/Co₃S₄/NiO ternary composites with 3D core-shell network structure is synthesized by using solvothermal method and high-temperature calcination method,which exhibites excellent energy storage performance with a high specific capacitance of 1069.4F·g^-1,an outsanding rate capability of 91.3%and an appealing cycle stability of 81.5%after 2500 cycles.In order to overcome the problem of high surface inertia and difficulty to combine of CNTs,nitrogen-doped carbon nanotubes（N-CNTs）are prepared by carbonizing polypyrrole nanotubes at high temperature,and then the N-CNTs/NiCo-LDH with 3D connected network structure are prepared by co-precipitation method.When the ratio of nickel to cobalt is 1:2,N-CNTs/Ni₁Co₂-LDH displays a charming specific capacitance of1311.8F·g^-1and a low charge transfer resistance of 0.21Ω.The above studies indicate that the CNTs-based composites with 3D network structure exhibit admirable performance in the application of supercapacitor,which expand a new idea for solving the problem of low specific capacitance of CNTs.Figure 79;Table 7;Reference 87...