N-CNTs/NiCo-LDH复合材料的制备及电化学性能

通过高温碳化聚吡咯纳米管制备了氮掺杂碳纳米管(N-CNTs), 并采用共沉淀法将镍钴层状双氢氧化物(NiCo-LDH)原位生长在N-CNTs上, 制备出具有三维互联网状结构的N-CNTs/NiCo-LDH复合材料. 研究了镍钴摩尔比对N-CNTs/NiCo-LDH复合材料形貌结构和电化学性能的影响. 结果表明, 当镍钴摩尔比为1∶2时, N-CNTs/Ni₁Co₂-LDH具有最佳的电化学性能. 在1 A/g电流密度下, 其比电容可达1311.8 F/g; 当电流密度为 10 A/g时, 电容保持率高达88.3%, 展现出优异的倍率性; 在经过2500次循环后, 电容保持率仍可达76.4%, 具有良好的循环稳定性.由N-CNTs/Ni₁Co₂-LDH与活性炭(AC)电极所构建的N-CNTs/Ni₁Co₂-LDH//AC水系混合型超级电容器, 在750 W/kg功率密度下, 具有27.19 W·h/kg的高能量密度.

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 coprecipitation 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/Ni₁Co₂-LDH 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·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.