温度及搅拌速度对纳米氢氧化镍性能的影响

采用化学沉淀法制备出片状和棒状混合的纳米β-Ni（OH）_2,将纳米粉体以 8%比例掺入到球镍中制成复合电极,研究了反应温度和搅拌速度对纳米粉体结构、形貌及其复合电极电化学性能的影响,结果表明,反应温度升高,纳米颗粒粒径增大;搅拌速度提高,粒径减小;复合电极的放电比容量随反应温度和搅拌速度提高先增大后减小,当反应温度为 50℃、搅拌速度为 600 r/min时,相应的复合电极放电比容量最大,达到了 263.3 mAh/g,比纯球镍电极放电比容量（239.4 mAh/g）提高了约 10%。研究还显示,复合电极的放电比容量与其粉体的压实密度有直接对应关系,其放电比容量和放电平台均高于纯球镍电极。     

纳米锡铜复合氧化物的制备与电化学性能

采用沉淀法制备了作为锂离子电池负极材料的纳米锡铜复合氧化物粉末,并用X射线衍射对其结构进行了分析、透射电镜对其形貌进行了表征、充放电和循环伏安法等对其电化学性能进行了测试.结果表明:采用沉淀法可以制备出颗粒粒度较均匀、尺寸为90nm的锡铜复合氧化物;充放电30次到50次,锡铜复合氧化物放电容量由254.4mAh/g衰减到241.1mAh/g,放电容量保持率较高(95%),说明纳米锡铜复合氧化物具有较高的放电容量和良好的循环性能。     

混合氨-碱沉淀剂制备Ni(OH)_2/还原氧化石墨烯复合材料及其电化学性能

利用简单易行的化学沉淀-回流法制备了Ni(OH)_2/还原氧化石墨烯(RGO)复合材料,研究了不同混合氨-碱沉淀剂对复合材料电化学性能的影响。采用XRD、拉曼光谱(Raman)和SEM表征Ni(OH)_2/RGO复合材料的微观结构和形貌。当以NH_3·H_2O-NaOH作为沉淀剂时,Ni(OH)_2/RGO复合材料中β-Ni(OH)_2纳米片均匀分散在石墨烯片层之间,形成相互插层结构。利用循环伏安(CV)、恒电流充放电(GCD)和电化学交流阻抗(EIS)测试了复合电极材料的电化学性能。研究结果表明:放电倍率为0.2C时,Ni(OH)_2/RGO复合电极材料的放电比容量达到344.8mAh/g,比β-Ni(OH)2的放电比容量高出约29%;5C时放电比容量为274.5mAh/g,经过50个循环,容量保持率为98.8%,呈现出良好的倍率性能和循环性能。     

淀粉还原制备纳米MnO_2超级电容器电极材料

采用氧化交联淀粉还原高锰酸钾制备出了超级电容器纳米MnO2电极材料.通过XRD和SEM对电极材料进行了表征,采用电化学测试手段对电极材料在lmol/L Na2SO4溶液中的电容特性和比容量进行了分析.结果表明,采用该方法所制备的材料为无定型的(а-MnO2,颗粒尺寸在100～150nm左右;循环伏安和恒流充放电试验测试结果表明,а-MnO2电极具有良好的电容特性.在放电电流为100 mA/g时,其比容量高达158 F/g.     

Ni(OH)_2/RGO复合材料的化学沉淀-回流法制备和放电性能

以氧化石墨(GO)和NiSO_4·6H_2O为前驱体,氨水为沉淀剂,用化学沉淀-回流法制备Ni(OH)_2/还原氧化石墨烯(RGO)复合材料,用XRD、SEM表征材料的结构和表面微观形貌,用循环伏安(CV)、恒电流充放电和电化学阻抗(EIS)测试电极材料的电化学性能,研究了GO:Ni(OH)_2质量比和氨水浓度对复合材料结构、形貌和电化学性能的影响。结果表明:所制备的β-Ni(OH)_2/RGO复合材料为Ni(OH)_2纳米片与RGO片相互插层的结构,当氨水的浓度为3 mol/L,GO:Ni(OH)_2=1:8(质量比)时复合电极材料在0.2C的放电比容量高达334.9 mAh/g,5C的放电比容量为260.2 mAh/g,保持在β-Ni(OH)_2理论比容量的90%,表现出良好的倍率性能和循环性能。     

Ni (OH)2-碳纳米管-还原氧化石墨烯复合材料的制备及电化学性能

利用简单易行的一步水热法制备了Ni（OH）₂-碳纳米管-还原氧化石墨烯（Ni（OH）₂-CNTs-RGO）三元复合材料,研究了不同水热反应温度对三元复合材料性能的影响。采用XRD、FTIR、Raman、X射线光电子能谱（XPS）、SEM及TEM对Ni（OH）₂-CNTs-RGO复合材料的结构和表面微观形貌进行表征。利用循环伏安（CV）、电化学交流阻抗（EIS）和恒电流充放电测试了复合电极材料的电化学性能。研究结果表明,当反应温度为120℃时,所制备的Ni（OH）₂-CNTs-RGO复合材料具有大的比表面积和三维网状结构,复合材料中六角形的β-Ni（OH）₂纳米片和CNTs均匀分散在RGO片层表面,有效阻止了RGO的团聚。Ni（OH）₂-CNTs-RGO复合电极材料在充电倍率为0.2 C时,放电比容量达到362.8 mAh/g,5 C时放电比容量为286.2 mAh/g,仍大于Ni（OH）₂在0.2 C时的放电比容量,表明CNTs与RGO的协同作用有效提高了电极材料的导电性和活性物质的利用率,最终提升了Ni（OH）₂-CNTs-RGO复合材料的倍率性能。     

静电纺丝法制备壳聚糖/聚乙烯醇基复合碳纳米纤维及其电化学性能

本工作观察并研究了不同碳化温度下制备的静电纺丝壳聚糖/聚乙烯醇基复合碳纳米纤维膜用作超级电容器电极材料时的电化学性能。通过SEM、XRD、Raman等技术对不同碳化温度得到的碳纳米纤维膜进行结构表征,利用循环伏安法(CV)和恒电流充电/放电(GCD)等电化学技术对不同碳化温度得到的碳纳米纤维膜进行电化学性能测试。结果表明,碳化温度为700℃时所制备的复合碳纳米纤维具有较好的电化学性能,在电流密度为1 A/g时放电比电容高达215 F/g,且循环4 000次后容量保持率几乎高达100%,表现出较高的放电比电容和较好的循环稳定性。     

添加有NiOOH的混合晶型Ni(OH)_2的电化学性能研究

采用络合沉淀法制备了具有特殊表面纳米片状结构的微米级混合晶型氢氧化镍,并研究了添加化学氧化NiOOH纳米颗粒对上述材料电化学性能的影响.采用SEM、XRD等手段表征了样品的形貌及物相特征,并考察了其作为镍氢电池正极活性材料的电化学性能.结果表明:添加的纳米片状β-NiOOH随机分布在氢氧化镍表面.以制备的样品为正极材料组装成镍氢模拟电池,在0.2C充放电条件下,制备材料的放电比容量可达306mAh/g;添加NiOOH能有效地改善镍电极的电化学性能,添加量为7wt%时,0.2C充放电条件下样品放电比容量为326mAh/g,在2C充放电条件下放电比容量可达311mAh/g.     

纳米铝粒子电极的脱/嵌锂离子特性

带直流电弧等离子体气相蒸发法制备球状Al纳米粒子,并对其进行了XRD、TEM以及电极的脱/嵌锂离子循环性能表征。结果表明,制备出的Al粒子大小约为100 nm,表面包覆一层厚度不到1nm的非晶氧化物。使用Al纳米粒子制做的负极极片组装电池,研究了电流密度对其电化学特性的影响。结果表明,电池的首次充放电曲线和前10次循环性能曲线表明,电流密度最小的Al电极首次放电容量最大,为951.9 mAh/g.首次容量损失也最大,其循环稳定性能也相应变差:而电流密度最大的Al电极首次放电容量为879.7mAh/g,其循环稳定性能最佳。首次放电结束后,在电极材料中出现了两种化合物AlLi和Al₂Li₃,与测试出的放电容量相符。     

模板法合成孔状纳米级锂离子电池正极材料LiFePO4

采用表面活性剂为模板,通过分子自组装法合成了孔状纳米级锂离子正极材料LiFePO4.并结合XRD、SEM、N2吸附/脱附和充放电测试等手段,对合成材料的结构、形貌、孔的分布和电化学性能进行了分析.实验结果表明:表面活性剂为模板,通过高温烧结脱去可以形成纳米孔状的LiFePO4正极材料,在以0.1mA的电流下放电,首次放电比容量有125.5mA·h/g,循环20次后其比容量仍有120mA·h/g,保持率达95.6%.     

超级电容器用纳米炭黑电极的电化学性能

用高导电性、高比表面积的工业炭黑(BET表面积为1080m2/g)作为超级电容器的电极材料。利用循环伏安法研究了不同扫描速度对电极电容特性的影响以及不同循环次数对循环伏安曲线的影响,用不同大小电流恒流充放电研究其充放电性能。结果表明:循环伏安曲线为矩形特征,炭黑电极表现出典型的电容行为,扫描速度与比电容基本无关;恒流充放电的电压和时间关系为线性关系,电极的大电流充放电性能良好,电极的循环寿命高。     

中间相沥青基活性泡沫炭的制备及其电化学性能研究

以中间相沥青为前驱体,经自挥发发泡法、KOH活化法制备的中间相沥青基活性泡沫炭作为超级电容器电极材料。采用扫描电镜、X射线衍射和低温(77K)N2吸附法对中间相沥青基活性泡沫炭的表面形貌和微观结构进行表征。中间相沥青基活性泡沫炭的比表面积为2700m2/g,总孔孔容为1.487cm3/g。通过恒流充放电、循环伏安和交流阻抗测试,考察了中间相沥青基活性泡沫炭作为超级电容器电极材料的电化学性能。在电流密度为0.02A/g时,中间相沥青基活性泡沫炭的比容量为240.48F/g,能量密度为33.4Wh/kg;在电流密度为5A/g时,比容量为166.68F/g,具有良好的电化学特性。     

Electrochemical performance of conducting polymer and its nanocomposites prepared by chemical vapor phase polymerization method

In this work, conducting polymers poly(3,4-ethylenedioxythiophene) (PEDOT), PEDOT/carbon nanotubes (CNTs), and PEDOT/reduced graphene oxide (RGO) were prepared via an in situ chemical vapor phase polymerization (VPP) process. Experiment results showed that PEDOT and PEDOT nanocomposites were uniformly constructed in oxidant and oxidant nanocomposite films through a modifying template effect. The VPP PEDOT and its nanocomposites were built on aluminium film as supercapaitor electrode materials and electrochemical capacitive properties were investigated by using cycle voltammetry and charge/discharge techniques. The VPP PEDOT exhibited a specific capacitance of 92 F/g at a current density of 0.2 A/g. The VPP PEDOT composites consisting of CNTs and RGO displayed specific capacitances of 137 and 156 F/g, respectively, at the same current density. For VPP nanocomposites, more than 80 % of initial capacitance was retained after 1,000 charge/discharge cycles, suggesting a good cycling stability for electrochemical electrode materials. The good capacitive performance of the conducting polymer nanocomposites are contributed to the synergic effect of the two components.     

3D graphene/fly ash waste material for hybrid supercapacitor electrode: specific capacitance analysis

The performance of supercapacitor energy storage is depending on the type of the material that is used as supercapacitor electrode. Graphene has been widely used as the base material for a lot of applications due to its remarkable properties. In this research, we try to combine 3D Graphene with waste material fly ash to be used as the electrode of supercapacitor. Fly ash is a residual material from burning pulverized coal in electric generation power plants which contain metal oxide materials such as iron oxide and aluminum oxide. This residual material might be usable as an electrode for supercapacitor due to its material contained. As the base material, the 3D graphene was successfully fabricated by using low pressure chemical vapor deposition (LPCVD) method and afterwards the fly ash was coated on the top of 3D graphene. The chemical properties and surface structure of the electrode material was studied by using Raman spectroscopy and field emission scanning electron spectroscopy (FESEM). 3 electrode systems were used to analyze the cyclic voltammetry results. According to the results, they show that the highest specific capacitance of 3D graphene/fly ash (FA) was about 0.025 F/cm2 at the lowest scan rate of 5 mV/s and it is recommended to use as the supercapacitor electrode.     

超级电容器用中孔炭的研究

以石油焦为原料,运用化学活化法制备了超级电容器用高比表面积中孔活性炭。利用XRD、SEM和BET对实验制备的中孔炭进行了分析和表征。以实验制备的活性炭为超级电容器电极材料,利用恒流充放电测试对其电容特性进行了研究。结果表明,实验研制的活性炭的比表面积为1733m^2／g,中孔含量达到60．6％,在150mA／g的电流密度下其比容达到180F／g,而且基于实验研制的活性炭的超级电容器具有低内阻和良好的功率特性。     

Dioxythiophene-based polymer electrodes for supercapacitor modules

We report on the electrochemical and capacitive behaviors of poly(2,2-dimethyl-3,4-propylene-dioxythipohene) (PProDOT-Me2) films as polymeric electrodes in Type I electrochemical supercapacitors. The supercapacitor device displays robust capacitive charging/discharging behaviors with specific capacitance of 55 F/g, based on 60 μg of PProDOT-Me2 per electrode, that retains over 85% of its storage capacity after 32?000 redox cycles at 78% depth of discharge. Moreover, an appreciable average energy density of 6 Wh/kg has been calculated for the device, along with well-behaved and rapid capacitive responses to 1.0 V between 5 to 500 mV s(-1). Tandem electrochemical supercapacitors were assembled in series, in parallel, and in combinations of the two to widen the operating voltage window and to increase the capacitive currents. Four supercapacitors coupled in series exhibited a 4.0 V charging/discharging window, whereas assembly in parallel displayed a 4-fold increase in capacitance. Combinations of both serial and parallel assembly with six supercapacitors resulted in the extension of voltage to 3 V and a 2-fold increase in capacitive currents. Utilization of bipolar electrodes facilitated the encapsulation of tandem supercapacitors as individual, flexible, and lightweight supercapacitor modules.     

3D ordered NiO/silicon MCP array electrode materials for electrochemical supercapacitors

The preparation and electrochemical properties of 3D ordered nickel oxide/silicon microchannel plate (NiO/Si-MCP) array electrode materials for supercapacitors are studied. The Si-MCP fabricated by electrochemical etching is used as a 3D supporting structure for electrodes. The active NiO is synthesized by electroless plating of nickel on the surface of the Si-MCP followed by annealing under oxygen. The electrochemical properties of the NiO/Si-MCP nanocomposite electrode materials are studied using cyclic voltammetry (CV), chronopotentiometry, and electrochemical impedance spectroscopy (EIS) in a 2 M KOH solution. The results reveal typical electrochemical capacitive behavior in the potential range from −0.6 to 1.0 V. The specific capacitance of approximately 586.4 F g⁻¹ decreases slightly with 4.8% loss after 500 cycles. The linear and symmetrical charge/discharge curves are measured by chronopotentiometry. The NiO/Si-MCP composite is a promising electrode material for integrated supercapacitors.     

Nitrogen-doped multiwalled carbon nanotubes decorated with copper(I) oxide nanoparticles with enhanced capacitive properties

We report on the enhanced capacitive properties of a copper(I) oxide nanoparticle (Cu₂O NP)-decorated multiwalled carbon nanotube (MWCNT) forest with nitrogen (N) doping. A careful in situ solid-state dewetting and plasma doping method was developed that ensured homogeneous decoration and contamination-free Cu₂O NPs with N doping on the nanotube sidewalls. The morphology and structure of the hybrid materials were characterised by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy and X-ray photoemission spectroscopy. The electrochemical performance of the hybrid materials was investigated by cyclic voltammetry and galvanostatic charge/discharge tests in a 0.1 M Na₂SO₄ electrolyte. The electrochemical tests demonstrated that the Cu₂O NP/N-MWCNT electrode exhibits a specific capacitance up to 132.2 F g^?1 at a current density of 2.5 A g^?1, which is 30% higher than that of the pure MWCNT electrode. Furthermore, the electrode could retain the specific capacitance at 85% stability over 1000 cycles. These observations along with the simple assembly method for the hybrid materials suggest that the Cu₂O NP/N-MWCNT could be a promising electrode for supercapacitor applications.     

The effect of Ag loading on supercapacitor performance of graphene based nanocomposites

In the present study, we prepared reduced graphene oxide (rGO) decorated with Ag nanoparticles by a one pot, simultaneous reduction method. The effect of AgNO₃ amount on the chemical, morphological and electrochemical properties of binary rGO-Ag nanocomposite for supercapacitor application was investigated. The chemical and morphological characterization of prepared rGO-Ag nanocomposites was realized with field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). For supercapacitor application, electrochemical performance of the nanocomposites was investigated with cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. As a result of their excellent conductivity and spacer role which prevent aggregation of rGO nanosheets and maintain the electroactive surface area, Ag nanoparticles significantly enhance the electrochemical performance of the nanocomposite. The rGO-Ag nanoparticle nanocomposite exhibited a maximum specific capacitance of 34.2?mF?cm^?2 at 0.6?A?cm^?2 current density. The nanocomposite electrode also has excellent rate capability and cycle life. The capacitance retention of rGO-Ag electrode is 98% after 1000 charge-discharge cycle. The results showed that rGO-Ag nanocomposite is a building block for ternary or other multicomponent nanocomposites.     

Facile one-step hydrothermal synthesis of reduced graphene oxide/Co3O4 composites for supercapacitors

This paper reports a facile one-step hydrothermal treatment of graphene oxide (GO) and cobalt acetate (Co(Ac)₂) for preparing reduced GO (rGO)/Co₃O₄ composites which were used as electrode materials for supercapacitors containing electrolytes of 2 M KOH aqueous solution. The morphologies and structures of rGO/Co₃O₄ composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectrum, and N₂ adsorption–desorption isotherms. The electrochemical performances of two-electrode supercapacitors were evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. During the hydrothermal reaction, GO was reduced and 10–30 nm-sized Co₃O₄ nanoparticles were in situ grown onto the rGO sheets simultaneously. The effects of mass ratios of GO and Co(Ac)₂ on the performances of supercapacitors were investigated. In comparison with pure Co₃O₄-based supercapacitor, supercapacitors based on rGO/Co₃O₄ composites show better performances because both the specific surface areas and the electrical conductivities of electrode materials were increased by the introduction of rGO. When the mass ratio of GO and Co(Ac)₂ is 1:2, rGO/Co₃O₄ composite electrode exhibits the highest capacitance of 263.0 F/g at a constant current density of 0.2 A/g in a two-electrode supercapacitor. In addition, the supercapacitor shows high rate capability and long cyclic durability.