氧化镍/碳纳米管构筑准固态不对称超级电容器及电化学性能

以Ni(NO₃)₂为原料、NaOH为沉淀剂和羟基化碳纳米管（CNT）为基质首先制备了Ni(OH)₂/CNT复合材料, 然后将其于一定温度下煅烧，使其转变为NiO/CNT复合材料。用X射线粉末衍射仪（XRD）、场发射电子显微镜（FESEM）和透射电子显微镜（TEM）表征了样品的晶相与形貌，结果表明NiO纳米粒子紧密锚附在碳纳米管表面。复合材料可能的形成机理被提出。采用循环伏安法（CV）、单电极充放电和电化学阻抗研究了反应条件对其电化学性能的影响，确定最佳制备条件。将复合材料正极、活性炭负极和PVA-KOH电解质膜组装成准固态不对称超级电容器，电化学性能测试结果表明，在充放电电流密度11.2mA/cm²下，其比电容达到868.0F/g并保持稳定循环3700圈。7500次循环后，其比电容值仍有564.2F/g，显示出高的比电容和长的循环稳定性。

Quasi-solid-state asymmetric supercapacitor constructed with NiO/CNT composites and its electrochemical performance

With Ni(NO₃)₂ as nickel source, NaOH as precipitation agent and hydroxylated carbon nanotube (CNT) as substrate, Ni(OH)₂/CNT composites were firstly synthesized. And then, the Ni(OH)₂/CNT composites were calcined and transformed into NiO/CNT composites at fixed temperature. The phase and morphologies of the products were characterized by X-ray diffractometer (XRD), field-emitting scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results showed NiO nanoparticles had firmly anchored on the surface of CNT. The possible formation mechanism of the composites was proposed. The influence of reaction parameters on the electrochemical performances of the composites was investigated by cyclic voltammetry (CV) method, charge-discharge test of the single electrode and electrochemical impedance spectroscopy and then optimal reaction conditions were obtained accordingly. A quasi-solid-state asymmetric supercapacitor was assembled by using the composite as positive electrode, active carbon (AC) as negative electrode and poly(vinyl alcohol) (PVA)-KOH as solid polymer electrolyte. Test results of the electrochemical properties displayed that the quasi-solid-state asymmetric supercapacitor provided a specific capacitance of 868.0F/g for 3700 cycles under the current density of 11.2mA/cm². After 7500 cycles, the specific capacitance still retained 564.2F/g, which exhibited the supercapacitor's high specific capacitance and long cycle stability.