Preparation and Electrochemical Properties of N-CNTs/NiCo-LDH Composite

Nitrogen-doped carbon nanotubes(N-CNTs)were prepared by carbonizing polypyrrole nanotubes at high temperature,and nickel-cobalt layered double hydroxides(NiCo-LDH)were in situ grown on N-CNTs by coprecipita. tion method to produce N-CNTs/NiCo-LDH composite with three-dimensional interconnected network structure. The effect of different nickel/cobalt molar ratios on the morphology,structure and electrochemical properties of N-CNTs/ NiCo-LDH composite was investigated. The results showed that N-CNTs/Ni1Co2-LDH had the best electrochemical performance when the molar ratio of nickel/cobalt was 1:2. The specific capacitance can reach 1311.8 F/g at a current density of 1 A/g. When the current density was 10 A/g,the capacitance retention rate of N-CNTs/Ni1Co2-LDH was as high as 88.3%,showing excellent rate capability. After 2500 cycles,the capacitance retention rate of N-CNTs/Ni1Co2LDH can still reach 76.4%,revealing good cycling stability. In addition,the N-CNTs/Ni1Co2-LDH//AC aqueous hybrid supercapacitor assembled by using N-CNTs/Ni1Co2-LDH and activated carbon(AC) electrodes had a high energy density of 27.19 W center dot h/kg at 750 W/kg power density. The exceptional electrochemical performance indicated that N-CNTs/Ni1Co2-LDH composite had broad application prospects in energy storage.