MnOOH-石墨烯-泡沫镍自支撑复合电极的制备及其超级电容性能

Preparation of MnOOH-graphene-foam Ni self-supported composite electrode and its supercapacitive performance

  • 摘要: 采用气相沉积法和后续的电沉积法制备得到自支撑结构的MnOOH-石墨烯(graphene)-泡沫镍(NF)复合电极。使用XRD、SEM、XPS等方法对样品的物相、形貌和价态等进行表征,通过恒流充放电、循环伏安、交流阻抗等方法对电极的电化学性能进行研究。结果表明:该方法可以成功制备得到具有自支撑结构的MnOOH-graphene-NF复合电极,超薄的graphene层均匀覆盖在NF的表面,微米球状的MnOOH纳米片紧密覆盖在graphene的表面。该自支撑复合结构可以直接用作超级电容器电极进行测试,在5 mol/L KOH溶液中表现出了较大的赝电容储存能力。在0.5 A/g的电流密度下,最大比容量可达934 F/g。当电流密度提高为5 A/g时,比容量仍达771 F/g。当电流密度为2 A/g时,循环5000次后的容量保持率高达98%,库伦效率接近100%,表现出了良好的超级电容性能。本实验提供了一种制备自支撑MnOOH-graphene-NF复合电极的新方法,该复合电极有望成为一种潜在的新型超级电容器电极材料。

     

    Abstract: A self-supported electrode of MnOOH-graphene-foam Ni(NF) was synthesized by the method of vapor deposition and subsequent electrode position. Its physical properties including the phase, morphology and valence state were measured by the characterizations such as XRD, SEM and XPS, while the electrochemical performance was studied by constant current charge-discharge, cyclic voltammetry and the AC impedance technique. The results show that this method can be successfully used to prepare the self-supported MnOOH-graphene-NF electrode. The thin graphene layer is uniformly covered on the surface of NF, while the MnOOH microspheres are covered on the surface of graphene. The self-supported composite structure can be directly used as a supercapacitor electrode which shows great pseudocapacitance storage capacity in the electrolyte of 5 mol/L KOH. It can exhibit a large specific capacitance of 934 F/g at the current density of 0.5 A/g. When the current density increases to 5 A/g, the capacitance still remain at a high value of 771 F/g. The capacitance retention keeps at 98% after 5000 cycles at 2 A/g, and maintains a high coulombic efficiency close to 100%, indicating good supercapacitive performance. A new method was provided to synthesize the self-supported electrode of MnOOH-graphene-NF and it is expected to become a newly potential supercapacitor electrode material.

     

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