双电层电容器用新型无灰煤(HyperCoal)基活性炭的制备

以无灰煤(HyperCoal)为原料,KOH和CaCO3为活化剂制备了煤基活性炭,采用低温N2吸附法表征了活性炭的比表面积和孔结构,测定了活性炭用作双电层电容器(EDLC)电极材料的电化学性能。考察了炭化温度、活化温度、活化时间和活化剂对活性炭电容特性的影响。研究结果表明,比表面积和比电容随着炭化温度的升高而降低,活化温度过高或活化时间太长对比电容有不利影响。此外,CaCO3影响活化过程中孔的开发,显著降低所制备活性炭的比表面积和比电容。在炭化温度为500℃、活化温度为800℃、KOH与焦的质量比为4∶1和活化时间2 h下所得活性炭的比表面积和总孔容分别达到2 540 m2/g和1.65 cm3/g,该活性炭电极在0.5 mol/L TEABF4/PC电解液中的比电容达到最大值46.0 F/g。     

活化条件对活性碳纳米管比表面积的影响

以KOH为活化剂, 研究了多壁碳纳米管在制备活性碳纳米管过程中四个重要影响因素: 活化剂用量、活化温度、活化时间和活化过程中保护气体的流速对所得活性碳纳米管BET比表面积的影响并解释了原因. 研究表明上述四个因素都会对活性碳纳米管的比表面积产生较大的影响, 其中活化剂用量的影响最大, 在研究范围内可引起比表面积增大约241 m²•g^-1. 在这四个影响因素中除活性碳纳米管的比表面积随活化温度的增加而不断增加外, 其他三个影响因素的变化都会使活性碳纳米管的比表面积出现最大值, 而且四个影响因素的改变, 都不改变活性碳纳米管的孔洞主要是中孔和大孔的特点.     

二氧化锰氧化制备聚苯胺及其超级电容性能

以二氧化锰为氧化剂在酸水体系中化学氧化制备了聚苯胺(PANI),考察了聚合条件对产率的影响。采用红外光谱、扫描电镜等手段对PANI的结构与形貌进行了表征,采用电化学工作站对其电化学电容性能进行了测试。结果表明:PANI产率随着体系中氧化剂用量的增加、苯胺用量的减少、反应温度的降低和反应时间的延长而增加,制备的聚苯胺主要是翡翠亚胺型聚苯胺,并以颗粒形式存在,大小在100 nm左右,局部有团聚现象,颗粒间堆积蓬松;该聚苯胺作为超级电容器活性电极材料,具有较好的电化学电容性能,最高比电容达到178 F/g。     

链珠状氢氧化亚镍的准电容特性及其在复合型超电容器中的应用(英)

本文采用溶胶凝聚方法制备了超细氢氧化亚镍电极材料并通过在其中掺加适量碳纳米管的方法大大提高了电极的比容量并有效改善了电极材料的阻抗特性。掺有20%碳纳米管的氢氧化亚镍复合电极材料的单电极比容量可达到320 F·g^-1。本文分别采用氢氧化亚镍/碳纳米管复合电极作为正极，活性炭作为负极，6 mol·L^-1 KOH作为电解液制备了复合型电化学电容器。采用上述方法制备的复合型电容器工作电压达到1.6 V，电容器质量比容量达到60 F·g^-1。复合型电容器能量密度达到20.11 Wh·kg^-1，最大功率密度达到8.6 kW·kg^-1,兼具高能量特性和优良的大电流放电特性。     

电解液离子与炭电极双电层电容的关系

以酚醛树脂基纳米孔玻态炭(NPGC)为电极, 通过微分电容伏安曲线的测试, 研究了水相体系电解液离子与多孔炭电极双电层电容的关系. 结果表明, 稀溶液中, 多孔炭电极的微分电容曲线在零电荷点(PZC)处呈现凹点, 电容降低, 双电层电容受扩散层的影响显著；若孔径小, 离子内扩散阻力大, 电容下降更为迅速, 扩散层对双电层电容的影响增大. 而增大炭材料的孔径或电解液浓度, 可明显减弱甚至消除扩散层对电容的影响. 炭电极的单位面积微分电容高, 仅表明孔表面利用率高, 如欲获得高的电容量, 还要有大的比表面积. 离子水化对炭电极的电容产生不利影响, 选用大离子和增大炭材料的孔径, 可有效降低离子水化对炭电极电容性能的影响.     

壳聚糖基多孔碳材料的制备及其超级电容性能

以胶态SiO₂纳米粒子为模板,壳聚糖为碳源,ZnCl2为活化剂,制备了具有不同比表面积和孔体积的氮掺杂介孔碳。采用多种表征手段对碳材料的微观形貌、比表面积和孔道结构进行了表征,探究了壳聚糖与SiO₂纳米粒子的比例以及ZnCl2活化剂对碳材料孔体积和比表面积的影响。结果表明,在未使用活化剂时碳材料(CSi-1.75)的孔体积高达4.53 cm³·g^-1,但其比表面积最小(729 m²·g^-1);使用ZnCl₂作为活化剂制备的碳材料(CSi-1.75-Zn)比表面积为1032 m²·g^-1,但其孔体积下降到1.99 cm³·g^-1,且具有最多的吡啶氮和吡咯氮。在以6.0 mol·L^-1 KOH为电解液的三电极体系中,当电流密度为0.5 A·g^-1时,CSi-1.75-Zn的比电容为344 F·g^-1,而CSi-1.75的比电容仅为255 F·g^-1。这表明碳材料的比表面积对超级电容性能影响最大,而孔体积影响较小。电容贡献分析结果表明,相对于CSi-1.75,CSi-1.75-Zn的双电层电容和赝电容都得到了提高,这表明更大的比表面积和更多的吡啶氮和吡咯氮有利于提高碳材料的超级电容性能。     

壳聚糖基多孔碳材料的制备及其超级电容性能

以胶态SiO₂纳米粒子为模板,壳聚糖为碳源,ZnCl₂为活化剂,制备了具有不同比表面积和孔体积的氮掺杂介孔碳。采用多种表征手段对碳材料的微观形貌、比表面积和孔道结构进行了表征,探究了壳聚糖与SiO₂纳米粒子的比例以及ZnCl₂活化剂对碳材料孔体积和比表面积的影响。结果表明,在未使用活化剂时碳材料(CSi-1.75)的孔体积高达4.53 cm³·g^-1,但其比表面积最小(729 m²·g^-1);使用ZnCl₂作为活化剂制备的碳材料(CSi-1.75-Zn)比表面积为1 032 m²·g^-1,但其孔体积下降到1.99 cm³·g^-1,且具有最多的吡啶氮和吡咯氮。在以6.0 mol·L^-1KOH为电解液的三电极体系中,当电流密度为0.5 A·g^-1时,CSi-1.75...     

EDLC用分级孔炭电极材料的制备与超电容性能研究

采用有机-有机自组装法和化学活化法相结合,制备了分级孔炭电极材料(HPC)。氮气静态吸附测试表明,化学活化使介孔炭的孔壁上产生了大量的微孔,从而使其比表面积大大增加。与以硬模板法制备的有序介孔炭(OMC)相比,HPC比OMC具有更为优异的电化学性能,这是因为微孔和介孔直接相连的分级孔结构,不仅增大了比表面积,而且能够显著减小电解质离子在电极材料孔道内的扩散阻力。     

自支撑硫镍基电极材料制备及其赝电容性能

硫镍基赝电容超级电容器具有较高的比电容和功率密度等优点,是下一代理想的储能装置之一,但其实际应用受到其活性材料的制约,如导电性低和循环性能差等。研究者围绕增强硫镍基赝电容电极材料导电性和提升循环稳定性进行了大量的研究工作。其中,构建自支撑的电极材料被认为是一种降低活性材料和集流体之间界面电阻的有效方法。本文综述了制备自支撑硫镍基赝电容电极的常见方法,并就活性材料的形貌与性能关系进行了总结,主要着眼于集流体改性、离子掺杂、复合材料构建及形貌调控优化等。最后对自支撑硫镍基赝电容电极材料的研究方向进行了展望。     

顺序加料法制备聚苯胺与聚吡咯复合物及其电化学电容性能

以顺序加料原位聚合法化学氧化制备了聚吡咯(PPy)和聚苯胺(PANi)的复合物.采用SEM、红外光谱表征其结构,采用电化学工作站测试其超级电容性能.结果表明:制得的聚苯胺与聚吡咯的复合物,形成了二次结构;复合物的循环伏安特性曲线均接近于理想的矩形,恒流充放电曲线基本为线性,呈现双电层电容;PANi-PPy和PPy-PANi复合物的最高比电容分别达到227.6、195.5 F/g.     

碳纳米管的功能化及其电化学性能

超级电容器作为一种新型的储能元件,以其快速储存、释放能量等优点,近年来成为各国科研工作的研究重点和焦点[1￣3],并在数据记忆存储系统、便携式仪器设备、后备电源、通讯设备、计算机、燃料电池、电动车混合电源等许多领域都有广泛的应用前景[4]。目前,超级电容器用的电极材     

Enhanced Capacitive Characteristics of Activated Carbon by Secondary Activation

The effect of the improvement of commercial activated carbon(AC) on its specific capacitance and high rate capability of double layer(dl) charging/discharging process has been studied. The improvement of AC was carried out via a secondary activation under steam in the presence of catalyst NiCl2, and the suitable condition was found to be a heat treatment at about 875 ℃ for 1 h. Under those conditions, the discharge specific capacitance of the improved AC increases up to 53. 67 F/g, showing an increase of about 25% as compared with that of as-received AC. The good rectangular-shaped voltammograms and A.C. impedance spectra prove that the high rate capability of the capacitor made of the improved AC is enhanced significantly. The capacitance resistance (RC) time constant of the capacitor containing the improved AC is 1.74 s, which is much lower than that of the one containing as-received AC(an RC value of 4. 73 s). It is noted that both kinds of AC samples show a similar specific surface area and pore size distribution, but some changes have taken place in the carbon surface groups, especially a decrease in the concentration of surface carbonyl groups after the improvement, which have been verified by means of X-photoelectron spectroscopy. Accordingly, it is suggested that the decrease in the concentration of surface carbonyl groups for the improved AC is beneficial to the organic electrolyte ion penetrating into the pores, thus leading to the increase in both the specific capacitance and high rate capability of the supercapacitor.     

Characterization of Microporous Activated Carbon Electrodes for Electric Double-layer Capacitors

IntroductionElectric double layer capacitors( EDLCs) witha high power density can be used as memory back-up devices or electric vehicles.EDLCs store energyin the electric double layer by charge accumulationon the interface between the electrode and the elec-trolyte. In order to obtain reasonable energies andpower densities,the more suitable material forEDLCs musthave a high surface area with a signif-icant value of specific double layer capacitance,better pore size distribution and electro…     

High Power Density Electric Double Layer Capacitor with Improved Activated Carbon

Introduction　　Recently ,therehasbeenanincreasinginterestinthedevelopmentofelectricdoublelayercapacitors (EDLCs)us inghighlyporouscarbonsastheelectrodematerialsduetotheirpossibletechnologicalapplicationsasenergystoragede vicespossessinghighpowerdensitycapability .1,2 Themainadvantagesofsuchdevicesaretheirpossiblehighratecapa bilityandlongcyclelifeascomparedtorechargeablebatter ies,butitsenergydensityislowerthanthatofrechargeablebatteries.Inordertoobtaintherequiredenergyandpowerdensity,EDLC…     

碳纳米管的活化处理及对其电化学容量影响的研究

采用KOH为活性剂,对碳纳米管进行活化处理,经透射电子显微镜和高分辨透射电子显微镜从不同角度观察,发现得到了两端开口,管长较短,管壁粗糙的活性碳纳米管．用氮气自动吸附仪测试了活化前后两种碳纳米管的比表面积,发现活性碳纳米管具有比活化前碳纳米管更高的有效比表面积,将这两种碳纳米管分别作为电极材料应用于电化学超级电容器,经测试,发现活化后的碳纳米管的电化学容量大大提高,在有机电解液中达到了50F／g．     

Secondary Activation of Commercial Activated Carbon and its Application in Electric Double Layer Capacitor

The cheap commercial activated carbon (AC) was improved through the secondary activation under steam in the presence of FeCl2 catalyst in the temperature range of 800-950℃ and its application in electric double layer capacitors(EDLCs) with organic electrolyte was studied. The re-acivation of AC results in the increases in both specific capacitance and high rate capability of DELCs. For AC treated under optimized conditions, its discharge specific capacitance increases up to 55.65F/g, an increase of about 33% as compared to the original AC, and the high rate capability was increased significantly.The good performances of EDLC with improved AC were correlated to the increasing mesoporous ratio.     

1-乙基-3-甲基咪唑三氟乙酸盐作为电化学双电层电容器电解液的电化学性能

应用循环伏安法和直流恒流充放电研究了以离子液体1-乙基-3-甲基咪唑三氟乙酸盐([EMIm]CF3COO)和高比表面活性炭电极构成的电化学双电层电容器的电化学性能.实验表明,[EMIm]CF3COO具有高的比电容、良好的循环特性以及高的充放电效率.在离子液体稳定的电化学窗口内,比电容随电化学窗口的增加而增大.能量密度随电流和电化学窗口的增加逐渐提高,功率密度随电流的增加而减小、随电化学窗口的增加而增加,是一种优良的电化学双电层电解液.     

Surface Modification and Performance of Activated Carbon Electrode Material

A commercial activated carbon was modified by surface treatment using three chemicals, nitric acid, hydrogen peroxide, and ammonia, respectively. The modified carbons were characterized by N₂ adsorption-desorption isotherms and FTIR spectroscopy. The resultant carbon electrode-based electric double-layer capacitors (EDLCs) were assembled with 6 mol·L⁻¹ KOH as the electrolyte. The influence of surface modification on the performance of EDLCs was studied by galvanostatic charge-discharge, cyclic voltammetry, and alternating current impedance. The surface modification resulted in no big decrease in specific surface area and little decrease in average pore size, and introduced functional groups, such as hydroxyl, carbonyl, and amidogen, on the carbon surface. These functional groups significantly improved the wettability and reduced the resistance of the activated carbon. As a result, the specific capacitance of the carbon modified with 65% HNO₃ reached 250 F·g⁻¹, 72.4% higher than that of original carbon. The leakage current of testing EDLCs decreased unexpectedly to 3-18 μA, only 0.8%-4.9% that of the original carbon electrode-based EDLC (371 μA).     

活性炭电极材料的表面改性和性能

以硝酸、双氧水、氨水三种化学试剂分别对活性炭进行表面改性, 用N2吸附法和FTIR表征炭材料改性前后孔结构和表面官能团的变化. 制备了以改性活性炭为电极材料, KOH溶液为电解质的模拟双电层电容器. 用恒流充放电、循环伏安、交流阻抗等方法考察了双电层电容器的电化学性能. 结果表明, 改性活性炭比表面积和平均孔径有所降低, 并且在炭材料表面引入了含氧或含氮官能团, 如—OH、>CO、—NH2等, 使炭材料的润湿性增强、电阻减小、电化学性能显著提高. 用65%硝酸改性后炭材料的比容量最高达到250 F·g-1, 比原样炭提高了72.4%; 实验电容器的漏电流急剧下降, 只有3-18 μA, 为原来电容器的漏电流(371 μA)的0.8%-4.9%.