石墨烯基复合超级电容器材料研究进展

石墨烯基复合材料因其优异的性能广泛应用于各个领域,尤其在超级电容器的研究中。本文对石墨烯基复合超级电容器材料的结构进行了分类,并分别从石墨烯-碳基复合材料、石墨烯-导电高分子复合材料、石墨烯-过渡金属化合物复合材料的角度,总结了不同石墨烯基复合超级电容器材料的研究进展,重点强调了优化电极结构和提高电极性能之间的关系。同时,概述了石墨烯基复合材料在锂离子电池、太阳能电池、催化等其他方面的应用。获得高能量密度、功率密度以及长循环寿命的超级电容器是其作为电极材料的发展趋势。     

石墨烯基柔性超级电容器复合电极材料的研究进展

近年来,便携式和可穿戴电子设备呈现出跨越式发展,为了使可穿戴电子器件更加灵活、轻巧、智能并完全实现产品化,就需进一步探求与之匹配的具有薄、轻、柔特点的储能装置。超级电容器由于具有功率密度高、循环寿命长、机械强度高、安全性好和易于组装等优点,受到研究者的广泛关注。然而,传统的超级电容器一旦受到外力发生变形,储能特性会极大降低甚至丧失。电极材料是电容器的核心部分,因此研制出高柔韧性和储能特性出众的电极材料是有必要的。石墨烯因具有大比表面积,优异的力学、电学性能而成为用于柔性超级电容器的有吸引力的电极材料。赝电容材料可提供高比电容,但其导电性差、稳定性低,因此研究者将石墨烯与赝电容材料相融合作为电极材料,充分发挥各自优势,不仅克服了石墨烯片层间易团聚的缺点,还可提高柔性超级电容器的整体能量密度。由于二维石墨烯片层易堆叠,电子传导能力受到限制,目前更多的研究工作致力于三维多孔网状结构的石墨烯材料。本文突出介绍了石墨烯的两个重要角色:(1)与电化学活性物质复合作为活性材料;(2)作为沉积活性物质的导电柔性基体。因此,功能多样化的石墨烯在制备柔性电极中有很大的潜力。通过化学沉积、浸涂、水热等工艺将具有高电导率的石墨烯直接作为柔性基底,或与赝电容材料键合附着在柔性基体上,制备基于石墨烯的柔性电极材料。本文介绍了超级电容器的储能原理和石墨烯在柔性超级电容器领域的应用状况,着重总结了石墨烯/过渡金属氧化物、石墨烯/导电聚合物复合电极材料在柔性超级电容器方面的研究进展;解析了柔性超级电容器电极材料仍然面临的挑战,并对其未来的发展进行了展望。     

石墨烯基超级电容器的发展现状与战略研究

超级电容器兼具普通电容器和化学电池的优点,具有功率密度高、可快速充放电、循环寿命长等显著优势。电极材料是发展具有优异性能超级电容器的关键材料。石墨烯凭借其优异的力学、电学、热学等性能成为超级电容器理想的电极材料。本文首先基于对石墨烯基超级电容器相关学术论文、专利的统计分析,讨论了石墨烯基超级电容器的发展现状与方向;其次,简要阐述了石墨烯基超级电容器在国内的产业发展现状,讨论了石墨烯基超级电容器未来发展所面临的难点与挑战,并在此基础上提出了未来发展的方向与建议。     

基于专利分析的石墨烯超级电容器技术发展趋势研究

利用Thomson Innovation数据库收录的全球石墨烯超级电容器领域的专利文献数据,研究了石墨烯超级电容器技术领域专利申请的整体态势、重点技术分布、地域分布、主要申请人和核心专利,全面揭示了石墨烯超级电容器的技术创新现状和发展趋势。研究发现:石墨烯超级电容器技术正处于快速发展阶段。超级电容器及其制造、电极及电极材料制备两个方向是研发热点。中、美、韩、日既是主要技术来源地,又是主要的技术目标地,此外,欧洲市场也处于相当重要的位置。美、韩、日重视全球专利技术布局,而中国专利较多但偏重于国内申请。石墨烯超级电容器核心技术主要掌握在美国手中。     

能源互联网背景下的新型碳材料在超级电容器储能技术中的应用与发展

超级电容器是一种介于传统静电容器和化学电池之间的新型储能元件,具有功率密度大、充放电速度快、使用寿命长、绿色环保等特点。而作为超级电容器重要的组成部分——电极材料,对超级电容器的电化学性能和市场应用起到重要的影响和制约。近年来,以碳气凝胶、碳纳米管、碳纤维和石墨烯等为代表的新型碳材料,成为超级电容器电极材料的研究热点,有望成为新一代电极材料。对近年来国内外关于新型碳材料的应用与发展进行了综述,并且展望了新型碳材料在超级电容器储能技术中亟需解决的问题和未来发展趋势,为构建能源互联网提供理论依据和技术支持。     

中科院研究发现高性能石墨烯基超级电容器

正近日,中科院电工所马衍伟课题组通过金属镁热还原二氧化碳气体,成功制备出富含孔道结构、高性能的石墨烯电极材料。相关成果发表在《科学报告》杂志上。超级电容器作为新型储能器件,具有功率密度高、充电时间短、使用寿命长等优点,但其能量密度一直受限于电极材料的性能。此次研制的基于石墨烯的超级电容器在水系和有机电解     

三维石墨烯网络在超级电容器中的应用（英文）

三维石墨烯网络(3DGNs)能够缩短电解质离子的扩散距离,提供快速电子输运通道,并能充当骨架以与赝电容材料进行复合,因而在超级电容器中得到了广泛应用。本文主要综述近年来三维石墨烯网络及其复合材料在超级电容器电极材料方面的的进展,论述提升三维石墨烯基超级电容器性能的途径,最后展望了未来三维石墨烯网络的前景。     

石墨烯/聚苯胺基超级电容器研究进展

近年来,超级电容器以其优异的性能引起了研究者的广泛兴趣。其中以石墨烯为基质的电极材料占研究的绝大部分,同时质子化的聚苯胺也是一种高比电容的电极材料,将石墨烯与聚苯胺复合,利用二者的协同作用可以有效提高电容器的性能。主要介绍了二者的复合方式及复合材料的电容性能,总结了石墨烯/聚苯胺电极材料电容器的研究进展,最后对该领域的发展进行了展望。     

超级电容器用石墨烯极片的制备和性能

以石墨粉为原料,通过简便的氧化还原法制备了石墨烯。将石墨烯极片在有机电解液体系中组装成超级电容器。利用XRD、SEM对制备的石墨烯电极进行物相和形貌分析。采用恒电流充放电、循环伏安和交流阻抗对所制备超级电容器的电容性能进行了研究。结果表明,石墨烯电极超级电容器比天然石墨制备的超级电容器的比电容有了明显的提高;在电流密度为200mA/g,电压区间为1.25~2.5V下循环888次后比电容保持在45.5F/g,容量保持率在85.5%,表明石墨烯材料制备的电容器具有较好的充放电循环性能。     

超级电容器用石墨烯极片的制备和性能

以石墨粉为原料,通过简便的氧化还原法制备了石墨烯。将石墨烯极片在有机电解液体系中组装成超级电容器。利用XRD、SEM对制备的石墨烯电极进行物相和形貌分析。采用恒电流充放电、循环伏安和交流阻抗对所制备超级电容器的电容性能进行了研究。结果表明,石墨烯电极超级电容器比天然石墨制备的超级电容器的比电容有了明显的提高;在电流密度为200mA/g,电压区间为1.25~2.5V下循环888次后比电容保持在45.5F/g,容量保持率在85.5%,表明石墨烯材料制备的电容器具有较好的充放电循环性能。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...