生物质衍生碳材料在超级电容器中的应用

能源和环境问题是人类可持续发展的关键问题,超级电容器作为一种新型的储能设备备受关注。碳材料作为超级电容器的电极材料,因具有良好的导电性、较大的比表面积及高稳定性被广泛应用。其中,以生物质作为前驱体制备所得的碳材料具有具有成本较低、来源广泛、形式多样等特点,同时此类材料表面常含有大量杂原子基团,大大提升了其相应的电容性能,因此受到了人们的广泛关注。本文介绍了部分以生物质为前驱体制备碳材料及其电容性能研究的工作。     

基于生物质制备多孔碳的电化学储能研究

近年来,大量化石燃料的使用改变了全球气候,加剧了温室效应并且产生了严重的热污染.能源枯竭和环境污染问题迫在眉睫,为实现生态环境的可持续发展,人们研究和开发了各种新型的储能材料和器件.超级电容器是最近几年发展迅速的一种新型储能装置,典型特点是储能和快速充放电.因为生物质绿色无污染、资源丰富和可再生,另外,生物质氮自掺杂炭材料因为孔隙发达、孔隙可调、耐酸碱、比表面积大,故可作为制备电极材料碳源的最优选择.本文分别以石榴籽和化妆棉两种生物质作为碳源,利用高温热解法来制备生物质氮自掺杂炭材料电极,并测其电化学性能.经过电化学测试得出,在1 A/g的电流密度下,石榴籽与KOH的质量比为3:1时比电容最大,约为295 F·g-1,同样电流密度下,化妆棉与KOH质量比为3:1时比电容最大,约为225 F·g-1.     

生物质基杂化水凝胶的制备及电化学性能

利用微波辅助水热法将黑液中的木质素与氧化石墨烯和生物基碳点进行自组装,制备出柔性杂化水凝胶(GO/HY/CD)。以GO/HY/CD₃为电极材料,在三电极体系中0.5 A/g的条件下获得了275 F/g的比电容。以GO/HY/CD₃电极和木质素水凝胶电解质组成的柔性固态超级电容器,在0.5 A/g电流密度下,比电容达到110 F/g。此外,使用复合电极的固态对称超级电容器器件表现出了良好的性能,为其在信号传感器和便携式储能设备中的应用提供了可能性。     

生物质基多孔碳在超级电容器中的应用进展

介绍了近期国内外生物质多孔碳的最新研究进展,并对以生物质作为前躯体制备多孔碳材料的制备方法、孔结构的控制以及微观形貌的调控等进行了综述,并对其在超级电容器中的应用情况进行了总结和展望。     

生物质碳基材料的制备及其在超级电容器中的应用

近年来,生物质碳基材料凭借其本身优异的化学性能引起研究者的青睐,本文主要介绍了超级电容器的构造及工作原理;综述了影响碳基超级电容器比容量大小的因素,并讨论了生物质在超级电容器中的应用及其应用前景。     

储能用生物质基先进碳材料的研究进展

简述了生物质基碳材料的储能机理及常用的制备方法;综述了形貌、类石墨结构、孔道以及表面官能团和杂原子掺杂等影响生物质基碳材料储能性能的规律和机理;最后对储能用生物质基碳材料未来的发展趋势和研究方向进行了展望。     

层次多孔碳的制备及其电化学性能的研究

以间苯二酚-甲醛(RF)作为碳源,利用具有中空结构的聚苯乙烯球(PS)作为模板,在高温下碳化得到三维层次多孔碳。采用扫描电镜、循环伏安及恒流充放电等方法对其性能进行测试。结果表明,层次多孔碳在高倍率条件下具有优异的电化学性能。     

氮掺杂碳材料的制备及电容性能测试

随着经济社会的飞速发展,带来了能源危机,因此开发高效的清洁能源成为缓解危机的重要解决途径.超级电容器是一类新型储能器件,它具有良好的充放电效率、循环寿命长、稳定性能好、对环境无污染等优点,因此开发高效、可持续发展的电极材料是提升其电化学性能的主要途径.以三聚氰胺为原料,二茂铁为复合材料,用KOH在氮气气氛下经高温活化制备样品,对样品进行电化学测试研究其电容性能.测试结果表明:样品具有良好的电容性能,且由于氮原子的引入,增加了材料的导电性,减小了电阻,说明所制备的样品具有良好的电容性能.     

碳分子筛基多孔碳材料在不同水系电解液中的超电容性能

电解液是超级电容器不可或缺的重要组成部分,水系电解液由于导电率高、安全性好且成本低而被广泛使用.本文以商品化碳分子筛为前驱体,采用KOH活化法制备了一种多孔碳材料AMS,并研究了其在KOH、K2 SO4、KNO3、NaNO3、LiNO3、KCl等6种水系电解液中的电化学性能.AMS在KOH电解液中具有108 F·g-1...     

Electrochemical energy storage performance of heterostructured SnO2@MnO2 nanoflakes

In this work, we report synthesis of SnO₂@MnO₂ nanoflakes grown on nickel foam through a facile two-step hydrothermal route. The as-obtained products are characterized by series of techniques such as scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The as-obtained SnO₂@MnO₂ nanoflakes are directly used as supercapacitor electrode materials. The results show that the electrode possesses a high discharge areal capacitance of 1231.6 mF cm⁻² at 1 mA cm⁻² and benign cycling stability with 67.2% of initial areal capacitance retention when the current density is 10 mA cm⁻² after 6000 cycles. Moreover, the heterostructured electrode shows 41.1% retention of the initial capacitance when the current densities change from 1 to 10 mA cm⁻², which reveals good rate capability. SnO₂@MnO₂ nanoflakes products which possess excellent electrochemical properties might be used as potential electrode materials for supercapacitor applications.     

多孔炭材料设计合成及电化学储能应用

多孔炭材料具有导电性好、结构稳定、资源丰富、价格低廉的天然优势,既可直接作为电极材料,构建炭基电化学储能器件,又可与非炭电活性材料复合,起到传输电子、缓冲体积膨胀及调节界面反应的作用,在电化学储能器件中一直发挥着不可或缺的作用。结合本文作者课题组的研究工作,本文总结了多孔炭制备及孔结构和形貌的调控方法,分析了各方法的优缺点;并以超级电容器、锂离子/钠离子电池和锂硫电池为代表,阐述了多孔炭材料在电化学储能领域的作用及应用研究现状,讨论了电化学储能器件对多孔炭材料的结构与性能要求,指出了多孔炭在电化学储能应用中存在的局限性,并对多孔炭在这些储能领域的研究和发展趋势做出展望。     

Electrochemical energy storage in ordered porous carbon materials

Highly ordered porous carbon materials obtained by a replica technique have been used for supercapacitor application and electrochemical hydrogen storage. For the preparation of the well-tailored carbons, MCM-48, SBA-15 and MSU-1 molecular sieves served as templates, whereas a sucrose solution, propylene and pitch were the carbon source. A careful physico-chemical characterization (CO₂ and N₂ adsorption, X-ray diffraction, electron microscopy observations) allowed to estimate the total surface area, the pore size distribution, the micro/mesopore volume as well as the structure and the microtexture of the investigated carbons. The specific capacitance (F/g) and the hydrogen adsorption capacity in the carbon nanopores were correlated with the microtextural properties. Especially, a linear dependence has been found between the capacitance or the amount of electrochemically stored hydrogen and the ultramicropores (pores smaller than 0.7 nm) volume. It clearly indicates that in these carbons: (a) the major part of the electrical double layer is charged with non-solvated ions; (b) ultramicropores play a determinant role for hydrogen storage.     

添加碳素复(混)合相变储热材料的研究及应用进展

相变储热材料因具有储热密度大、相变温度变化小且过程易控制等优点而在许多领域具有重要应用。但传统的相变储热材料存在导热系数低及固-液相变过程中液态泄漏问题,阻碍了其实际应用。碳材料如石墨、碳纤维、碳泡沫和膨胀石墨,他们都具有高导热系数、低密度和良好的化学稳定性。将碳材料添加到相变储热材料中或与相变储热材料进行复合,从而构成碳素复(混)合相变储热材料,储热材料的导热系数及其性能可明显提高。本文综述了碳素复(混)合相变储热材料的研究进展。利用膨胀石墨的多孔特性吸附有机物制备膨胀石墨基复合相变储热材料,其储热密度大、导热系数高、性能稳定、成本低且在固-液相变过程中没有液态的流动性问题,是未来研究和应用最重要的碳素复合相变储热材料。     

秸秆基碳材料在Li2SO4电解液中的电化学性能

以生物质秸秆为碳源,利用水热结合KOH活化法制备了多孔碳材料,对其结构与形貌进行了表征。采用三电极体系,在不同浓度的Li₂SO₄电解液中,对多孔碳电极进行循环伏安、恒电流充放电和交流阻抗测试。结果表明,在0.5 mol·L^-1的Li₂SO₄电解液中,秸秆基生物质碳材料呈现出较好的电化学性能。当电流密度为0.5 A·g^-1时,比电容可达224 F·g^-1;经1500次充放电测试后,比电容保持率高达94.1%,循环性能良好。     

Electrochemical energy storage applications of carbon nanotube supported heterogeneous metal sulfide electrodes

Electrochemical system centered on hierarchically carbon-based metal sulphide assemblies are of great fame for competent supercapacitors. Herein, the synthesis of a hierarchical CNT anchored MoS₂–Bi₂S₃ nanocomposite is reported. Attractively, a vertically grown Bi₂S₃ nanorods supported on MoS₂ nanosheets with carbon framework acts as a highly effective electrode in alkaline electrolyte. More interestingly, this hierarchical structure and synergetic upshot of CNT and composites provide excess coverage of active sites with improved conductivity and stability. Advancing from the physical and compositional properties of nanocomposites, the specific capacitance of MoS₂–Bi₂S₃@CNT composites is measured to be 1338 F/g at 10 mV/s, columbic efficiency of 99.5% over 10000 cycles and long-term stability (60% retention at 0.5 A g^?1 over 2000 cycles and 34.6% up to 10000 cycles). The success of this MoS₂–Bi₂S₃@CNT composite may be attributed to the structural advantages, admirable cyclic stability, and better capacitance retention for supercapacitor applications.     

Nano-porous carbon materials derived from different biomasses for high performance supercapacitors

Nano-porous carbon materials derived from various natural plants are fabricated by a facile, cost-effective and efficient approach. The influence of well-dispersed intrinsic elements in different precursors and chemical activation process under different temperatures on the morphology, surface chemistry, textural structures and electrochemical performance have been studied and analysed in detail. These as-prepared nano-porous carbons possess high accessible surface area (685.75–3143.9 m² g⁻¹), well-developed microporosity and high content of naturally-derived heteroatom functionalities (16.43 wt%). When applied as electrode materials for supercapacitors in a three-electrode system with 6 M KOH, the obtained nano-porous carbons derived from lotus leaves at 700^oC possess a high specific capacitance of 343.1 F g⁻¹ at 0.5 A g⁻¹ and a capacitance retention of 96.2% after 10000 cycles at 5 A g⁻¹. The assembled symmetrical supercapacitor presents a high energy density of 24.4 Wh kg⁻¹ at a power density of 224.6 W kg⁻¹ in Na₂SO₄ gel electrolyte. This work provides guiding function for unified and large-scale utilization of agricultural biomass waste. The obtained sustainable activated carbon products can be used in diverse applications.     

Electrochemical storage of energy in carbon nanotubes and nanostructured carbons

Possibilities of electrochemical energy conversion using carbon nanotubes and related materials in various systems, such as lithium batteries, supercapacitors, hydrogen storage, are considered. It is shown that for these applications the electrochemical properties of multiwalled (MWNTs) and single walled (SWNTs) nanotubes are essentially dominated by their mesoporous character. During lithium insertion into nanotubular materials a high irreversible capacity C_irr (from 460 to 1080 mAh/g) has been observed after the first cycle with a tendency to further decomposition of electrolyte with cycling. Penetration of solvated lithium ions in the accessible mesopores is at the origin of this phenomenon; an almost linear dependence has been found between the mesopore volume and C_irr. Reversible capacity for lithium insertion C_rev ranged between 220 and 780 mAh/g; however, a great divergence (hysteresis) between insertion and extraction characteristics was observed independently on the kind of nanotubes and oxygen content. Amount of lithium stored by electrostatic attraction is negligible in comparison to real redox reactions which for thermodynamic reasons present linear variation of potential, especially during deinsertion (pseudocapacitive effects). During positive polarization, i.e., removal of lithium, resistivity of the electrode also gradually increases. Due to the open network of mesopores formed by the nanotubes entanglement, and consequently an easily accessible electrode-electrolyte interface, nanotubular materials are quite adapted for supercapacitor electrodes in various electrolytic solutions. High values of capacitance (80 F/g) have been obtained in 6 M KOH for materials with a surface area of only ca. 430 m²/g. Capacitance values have been enhanced either by additional oxygenated functionalisation of nanotubes (130 F/g) or by conducting polypyrrole (PPy) electrodeposition where the maximum values reached 170 F/g. The next domain of energy storage in the carbon nanostructures is the accumulation of hydrogen by the electrochemical decomposition of aqueous alkaline medium on a negatively polarized carbon electrode in ambient conditions. For SWNTs only moderate values (below 0.5 wt.% of H₂) have been found, while for activated carbons with highly developed surface area of 1500 m²/g, the amount of reversibly sorbed hydrogen was ca. 2 wt.%, noticeably larger than under dihydrogen pressure (only 0.4 wt.% for the same material at 70 bar and 273 K). The enhancement observed for the activated carbon is interpreted by the formation of nascent hydrogen during water reduction which penetrates easily in the available carbon nanopores. The values obtained by this method are comparable to those of metallic alloys, such as LaNi₅ for example.     

改性山核桃外果皮炭对碱性染料的吸附特性研究

用磷酸活化山核桃外果皮制备的生物质炭吸附剂处理碱性染料废水,研究了该吸附剂对废水中孔雀石绿(MG)和亚甲基蓝(MB)的吸附性能。结果表明,该吸附剂为高效的碱性有机染料吸附剂,当其投加量为1 g/L时,318 K条件下对初始质量浓度为300 mg/L的MG的去除率达99.20%,303 K条件下对初始质量浓度为200 mg/L的MB的去除率达98.48%;吸附动力学符合准二级动力学方程;等温吸附模型符合Langmuir方程。     

中温相变蓄热材料研究进展

对中温相变蓄热材料(PCM)的定义范畴、应用领域、国内外发展现状进行了评述。中温PCM主要针对90~550℃的热动力环境,在太阳能热发电、有机朗肯循环、移动蓄热技术、分布式能源系统等方面有广阔的应用前景。指出进一步的研究方向是拓展中温PCM的应用场合,规范长期稳定性的表征与测试手段,重视与换热器开发以及应用领域的整合,并提出硝酸盐熔融盐混和物将是今后一段时期内中温PCM研发和培育的重点产品对象。