假槟榔花基多孔炭材料的制备及其电化学性能研究

以假槟榔花为原料, 经高温碳化和氢氧化钾活化制备得到假槟榔花基多孔炭材料。采用XRD、SEM、热重分析仪、比表面积及孔径分析仪等对多孔炭材料进行表征和分析, 用电化学工作站和恒流充放电测试仪测试其电化学性能。结果表明, 假槟榔花基多孔炭材料为无定形炭材料, 为纳米片层结构, 比表面积为1 223.32 m²/g。三电极体系中, 以1 mol/L H₂SO₄和6 mol/L KOH为电解液, 电流密度为0.5 A/g时, 其放电比电容分别为145 F/g和105 F/g; 20 A/g电流密度下, 放电比电容分别为100 F/g和80 F/g。二电极体系中, 在酸和碱条件下, 1 A/g电流密度下循环5 000圈, 其电容保持率均在98%以上。该材料具有高的比表面积和纳米片层结构, 有利于提高材料的电荷储存能力, 材料具有良好的超级电容器特性。     

新型超级电容器电极材料NaxCo2O4的制备及电性能研究

采用溶胶-凝胶法制备得到Na x Co2O4(x=1.0、1.2、1.4、1.6、1.8和2.0)样品,并首次将其应用于超级电容器电极材料;经XRD、SEM和电性能研究得出,制备出的Na x Co2O4晶体均为层状结构,x=1.6时样品电容性能最好,在6mol/L NaOH电解液中,0.25~0.7V电压范围内,以50mA/g的电流密度进行恒流充放电,比电容高达413F/g。     

Preparation and electrochemical properties of poly‐2,5‐dihydroxyaniline/activated carbon composite electrode in organic electrolyte

Poly‐2,5‐dimethoxyaniline coating has been fabricated on active carbon (AC) substrates by cyclic voltammetry (CV) in organic system. The resulted coating is hydrolyzed to produce poly‐2,5‐dihydroxyaniline (PDHA) to enhance the capacitance of the composite electrode. Scanning electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, Raman spectra, CV, electrochemical impedance spectroscopy, and galvanostatic charge/discharge test are used to investigate the properties of these electrodes. In organic electrolyte, due to the introduced hydroquinone units, high value of capacitance up to 975 F g^?1 of the PDHA/AC has been obtained at a current density of 0.37 A g^?1 at a potential window of 0–1.5 V. An asymmetric capacitor has been assembled with the PDHA/AC positive and pure AC negative electrodes, which is able to obtain a specific energy as high as 178 Whkg^?1 in the potential range of 0–2.0 V at a current density of 0.93 A g^?1. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Electrochemical properties of MnO2/CNT nanocomposite in neutral aqueous electrolyte as cathode material for asymmetric supercapacitors

A MnO₂/carbon nanotube (CNT) nanocomposite was synthesised using a simple hydrothermal treatment. The nanocomposite exhibits a CNT core/MnO₂ porous sheath hierarchy architecture, which makes it promising as an electrode material for supercapacitors. An asymmetric supercapacitor based on activated carbon (AC) as anode, MnO₂/CNT nanocomposite as cathode and 1M Na₂SO₄ solution as electrolyte was assembled in a Swagelok cell. The full cell exhibits excellent power capability, cycling stability and a high energy density of 23 W h/kg at a power density of 330 W/kg based on the total mass of the active electrode materials. This AC//MnO₂/CNT asymmetric supercapacitor is promising for high-power applications due to its high energy density and power density.     

Electrochemical performance of carbon-coated lithium manganese silicate for asymmetric hybrid supercapacitors

Nanoscale carbon-coated Li₂MnSiO₄ powder is prepared using a conventional solid-state method and can be used as the negative electrode in a Li₂MnSiO₄/activated carbon (AC) hybrid supercapacitor. Carbon-coated Li₂MnSiO₄ material presents a well-developed orthorhombic crystal structure with a Pmn2₁ space group, although there is a small impurity of MnO. The maximum specific capacitance of the Li₂MnSiO₄/AC hybrid supercapacitor is 43.2 F g⁻¹ at 1 mA cm⁻² current density. The cell delivers a specific energy as high as 54 Wh kg⁻¹ at a specific power of 150 W kg⁻¹ and also exhibits an excellent cycle performance with more than 99% columbic efficiency and the maintenance of 85% of its initial capacitance after 1000 cycles.     

纳米氧化镍在超大容量电容器中的应用

用络合沉淀法制得Ni(OH)2，经过加热分解得纳米NiO粉末（粒径约30nm)。用该粉末作为活性物质制得的电极具有90－110F／g的比容量。考察了电极的比容量与电解液的浓度、工作电位范围的关系，并讨论了其储存电荷的机理。     

电化学还原法制备石墨烯膜电极

采用电化学还原法成功将氧化石墨烯还原,得到具有一定柔性的石墨烯膜。利用扫描电子显微镜法(SEM)、透射电子显微镜法(TEM)、拉曼光谱、X射线光电子光谱法(XPS)等测试手段对石墨烯材料的结构和形貌进行了表征;结果表明,所制备的石墨烯形貌较好、表面平整、无褶皱;通过测试其电化学性能对其还原电位、膜层厚度等制备条件进行了优化;当伏安循环电压范围为-2.0~2.0 V、膜厚度为1μm时,得到的石墨烯膜电化学性能优异,电流密度为0.1 A/g时,比电容可以达到123.8 F/g。     

Reed Leaves as a Sustainable Silica Source for 3D Mesoporous Nickel (Cobalt) Silicate Architectures Assembled into Ultrathin Nanoflakes for High‐Performance Supercapacitors

Mesoporous 3D architectures of silicon dioxide, nickel silicate, and cobalt silicate are for the first time prepared by using reed leafs as a sustainable silica source. Due to the 3D mesoporous architecture, nickel and cobalt silicate allow efficient charge transfer and mass transport, while at the same time buffering the volume changes during ion lithiation/delithiation processes. Especially, the nickel silicate electrode with the mesoporous 3D architecture shows a high specific capacitance, a good rate capability, and cycling stability for electrochemical capacitors.     

碳气凝胶/四氧化三钴复合材料的制备及电化学性能

采用电化学沉积法,以碳气凝胶(CA)为基底沉积氢氧化钴(Co(OH)2),并热处理制备碳气凝胶/四氧化三钴(CA/Co3O4)复合电极材料。采用XRD,SEM对样品的结构和微观形貌进行表征。采用循环伏安,恒电流充放电测试,交流阻抗测试对样品的电化学性能进行了表征和测试。研究结果表明,采用电化学沉积法制备的CA/Co3O4复合电极材料,在电流密度0.5和5 A/g时,其质量比容量分别为1 020和646 F/g。可见Co3O4的复合,能够很大程度的提升电化学性能。