超级电容器能量密度的提升策略

超级电容器最大的优点是具有优良的脉冲充放电性能和快速充放电性能,同时具有循环寿命长、工作温度范围宽、安全无污染等特性,但能量密度较低. 本文对超级电容器的工作原理、发展状况、缺陷所在和改进方法进行了简要介绍,以本课题组在高比能超级电容器方面的研究工作为主线,结合近几年的文献报道,重点阐述了超级电容器能量密度的提升策略. 主要围绕以下三个方面开展了工作：1）通过将电极材料尺寸纳米化来提高传统电极材料的比容量或开发其他高比容量的电极材料;2）发展具有高电压窗口的离子液体电解液,或利用不同材料在不同电位区间的电容特性构筑不对称电容器,从而提高超级电容器的电压窗口;3）将超级电容器和锂离子电池进行“内部交叉”构筑兼具高能量密度和高功率密度的锂离子混合电容器. 最后,对超级电容器的发展进行了展望.     

提高电容性电化学储能装置能量容量的一些尝试

本文从作者所在的课题组在超级电容器和超级电容电池方向的研究内容为基础,在电极材料和装置层面综述了电容性电化学储能装置的发展. 导电聚合物和过渡金属氧化物分别与碳纳米管复合后的复合物能显著提高前两者作为电容性法拉第储能电极的电容性能. 活性炭和碳黑等一类碳材料则可作为非法拉第储能的电极材料. 通过对超级电容器正负极电容做相应的匹配调整可以提高超级电容器的最大充电电压,从而提高超级电容器的能量容量. 此外,为了与实际设备相匹配,超级电容可以以双极板的方式串联堆积,满足高电压的需求. 超级电容电池作为新一代的电容性电化学储能装置,分别由具有电容性和法拉第电荷储存原理的电极组成,具有高比功率和高比能量的特点,也是近年来的研究热点.     

碳纳米管/石墨烯复合结构及其电化学电容行为

本文综述了超级电容器电极材料碳纳米管/石墨烯复合结构的制备方法,以及由该结构和赝电容活性物质形成的三元复合体系的电化学电容行为研究进展,并提出合理设计的碳纳米管和石墨烯复合结构可以有效发挥其高电导率、高比表面积和合理孔隙结构的优势,实现活性物质的高密度负载,从而获得具有高容量、良好倍率特性和长寿命的电化学超级电容器电极材料。     

用于超级电容器电极材料的石墨烯基纳米复合物的种类和研究现状

超级电容器是目前研究较多的新型储能元件,其大的比电容、高的循环稳定性以及快速的充放电过程等优良特性,使其在电能储存及转化方面得到广泛应用。超级电容器的电极材料是它的技术核心。石墨烯作为一种新型的纳米材料,具有良好的导电性和较大的比表面积,可作为超级电容器的电极材料。利用其他导电物质对石墨烯进行改性和复合,可以在保持其本身独特优点的同时提高作为电极材料的导电率、循环稳定性等其他性能。本文从半导体/石墨烯复合材料、金属及金属氧化物/石墨烯复合材料、石墨烯/导电聚合物复合材料3个方面综述了复合改性后的石墨烯在超级电容器电极材料方面的研究进展。通过对各复合物电极材料的制备方法和性能的对比分析,指出石墨烯基复合物作为超级电容器的电极材料的未来研究内容是开发低成本、高比容量和高循环稳定性的复合物。     

影响热还原氧化石墨烯超级电容器性能的因素比较

通过改进的Hummer法制得氧化石墨烯,并在不同温度的氩气气氛中还原得到一系列热还原氧化石墨烯（T-RGO）. 电化学测试表明,T-RGO作为超级电容器电极材料时,良好的导电性是必需的,但石墨烯表面含氧官能团对其电容性能的影响要远大于导电性和比表面积的影响,900 °C还原的T-RGO比表面积为314 m²·g^-1电导率为2421 S·m^-1,但其容量只有56 F·g^-1,然而300 °C还原的T-RGO比表面积为18.8 m²·g^-1电导率为574 S·m^-1,其容量却达到281 F·g^-1. 材料表征分析表明,300 °C 还原的石墨烯之所以有更高的电容,是因为除双电层电容外,更多的是由其表面含氧官能团提供的赝电容,这使作者以后在设计制备超级电容器等储能设备用石墨烯基电极材料时更加有针对性.     

花瓣状Co-Al双金属硫化物/泡沫镍电极材料的制备及其超级电容性能的研究

采用低成本的两步水热法直接将Co-Al双金属硫化物生长在泡沫镍上,成功制备了CoAl₂S₄/Ni电极材料,利用X射线衍射(XRD)、扫描电镜(SEM)和电化学测试等手段对其结构、形貌和超级电容性能进行了表征。结果表明,CoAl₂S₄/Ni电极材料呈现花瓣状的三维多孔结构,且表面粗糙,这种结构有利于电解液和电极材料的充分接触,具有良好的导电性和比电容性能;当电流密度为1A/g时,电极的放电比容量高达2187.1 F/g, 循环100次后比电容的保持率为90.1%,相关研究为超级电容器电极材料的制备及性能研究提供思路。     

有序介孔碳的简易模板法制备与电化学电容性能研究

0引言电化学电容器(Electrochemical Capacitors),又称为超级电容器(supercapacitors)是介于传统电容器和二次电池之间的一种新型储能装置,它具有循环寿命长、比容量高、能快速充放电等优点[1,2]。近年来随着电子、电气设备的日趋小型化以及电动汽车工业的不断发展,作为后备电源和记忆候补装置的超级电容器日益引起了人们的广泛关注。碳材料由于具有成本低、比表面积大、导电性优良、制备电极工艺简单等特点,一直是超级电容器电极材料的首选。其中,活性炭是最早采用的多孔电极材料,其比表面积可高达2500￣3000m·2g-1[3]。然而,活性炭材料…     

新型超级电容器的研发进展

传统超级电容器受低能量密度的限制,在当今器件研发中需更加关注电极材料结构-组成-性能研究。 本文总结了新型赝电容器的发展历程及其研发过程中存在的挑战与解决措施,着重从胶体离子超级电容器电极材料等新型的电极材料和氧化还原电解质两个方面进行综述。 原位合成的胶体离子超级电容器电极材料比非原位合成的电极材料具有更高的反应活性,并且以近似离子的状态存在,有效增加了电极材料的比容量。 氧化还原电解质的使用在不改变电极材料的前提下,进一步提高了超级电容器的能量密度。 初步介绍了新型锂离子电容器。 锂离子电容器同时使用电池型材料和电容型材料,可提高其能量密度。 依据当前超级电容器的研发现状,未来有望将电池材料和电容器材料结合使用,进而形成电池电容器或电容电池,使其同时具有高的能量密度和功率密度。     

提高电容性电化学储能装置能量容量的一些尝试（英文）

本文从作者所在的课题组在超级电容器和超级电容电池方向的研究内容为基础,在电极材料和装置层面综述了电容性电化学储能装置的发展.导电聚合物和过渡金属氧化物分别与碳纳米管复合后的复合物能显著提高前两者作为电容性法拉第储能电极的电容性能.活性碳和碳黑等一类碳材料则可作为非法拉第储能的电极材料.通过对超级电容器正负极电容做相应的匹配调整可以提高超级电容器的最大充电电压,从而提高超级电容器的能量容量.此外,为了与实际设备相匹配,超级电容可以以双极板的方式串联堆积,满足高电压的需求.超级电容电池作为新一代的电容性电化学储能装置,分别由具有电容性和法拉第电荷储存原理的电极组成,具有高比功率和高比能量的特点,也是近年来的研究热点.     

高比能超级电容器的研究进展

与传统蓄电池相比,超级电容器具有高功率密度、长循环寿命和使用温度范围宽等优势,但其能量密度较低.本文对超级电容器的结构、分类以及发展状况进行了简要介绍,重点阐述了本实验室近年来在研制高性能超级电容器方面的相关工作.主要从两个方面来提高超级电容器的能量密度:(1)通过采用中性水系电解液、有机电解液和离子液体提高对称型碳基超级电容器的电压窗口;(2)应用非对称型超级电容器,即一个电极采用具有法拉第赝电容电极材料或电池电极材料,而另一个电极则采用具有双电层电容的电极材料.同时介绍了由锂离子电池电极材料/活性炭作为正极,石墨作为负极组成的锂离子混合型超级电容器.最后,对超级电容器的发展方向进行了展望.     

活性炭二次活化对其电化学容量的影响

为进一步提高作为电化学超级电容器电极材料活性炭的电化学容量, 采用KOH作为二次活性剂, 将所得活性炭进行二次化学活化处理, 从而得到二次活化活性炭. 将原始活性炭材料与二次活化活性炭材料都分别经过系列处理, 组装成电化学超级电容器进行电化学性能测试. 测试结果表明, 二次活化活性炭材料的电化学容量达到145.0 F·g-1(有机电解液), 远远大于原活性炭材料的容量(45.0 F·g-1). 为研究二次活化活性炭材料电化学容量大幅提高的原因, 将这两种材料分别进行微观结构数据测试, 包括比表面积、N2吸脱附等温曲线和孔径分布. 研究结果表明, 二次活化处理大大增加了二次活化活性炭材料在孔径为2-3 nm的中孔分布, 从而证实对于有机电解液, 电极材料在2-3 nm的中孔对其电化学容量的提高具有重要意义.     

Surface modification by graphene oxide:An efficient strategy to improve the performance of activated carbon based supercapacitors

An efficient and cost-effective strategy to modificate the surface of active carbon (AC), form a 3D-conductive network, and therefore improve the electrochemical performance of AC based supercapacitor was developed.     

用于超级电容器的锰钴氧化物/碳纤维材料

The development of high-performance supercapacitor electrode materials is imperative to alleviate the ongoing energy crisis. Numerous transition metals (oxides) have been studied as electrode materials for supercapacitors owing to their low cost, environmental-friendliness, and excellent electrochemical performance. Among the developed binary transition metal oxides, manganese cobalt oxides typically show high theoretical capacitance and stable electrochemical performance, and are widely used in the electrode materials of supercapacitors. However, the poor conductivity and active material utilization of manganese cobalt oxide-based electrode materials limit their potential capacitance application. Cotton is mainly composed of organic carbon-containing materials, which can be transformed to carbon fibers after calcination. The resultant carbonaceous material exhibits a large specific surface area and good conductivity. Such advantages could potentially suppress the negative effects caused by the poor conductivity and small specific surface area of manganese cobalt oxides, thereby improving the electrochemical performance. Herein, we firstly deposited manganese cobalt oxides on cotton by a simple hydrothermal method, yielding a composite of manganese cobalt oxides and carbon fibers via subsequent calcination, to improve the electrochemical performance of the electrode material. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and electrochemical characterizations were used to investigate the physical, chemical, and electrochemical properties of the prepared samples. The fabricated manganese cobalt oxides in the composite were uniformly dispersed on the carbon fiber surface, which increased the contact between the interface of the electrode material and electrolyte, and enhanced electrode material utilization. The electrode material was confirmed to have well contacted with the electrolyte during a contact angle test. Hence, a pseudo-capacitance reaction completely occurred on the manganese cobalt oxide material. Moreover, the addition of carbon fibers reduced the resistance of the material, resulting in excellent capacitive performance. The capacitance of the prepared composite was 854 F∙g^-1 at a current density of 2 A∙g^-1. The capacitance was maintained at 72.3% after 2000 cycles at a current density of 2 A∙g^-1. These results indicate that the manganese cobalt oxide and carbon fiber composite is a promising electrode material for high-performance supercapacitors. The findings presented herein provide a strategy for coupling with carbon materials to enhance the performance of supercapacitor electrode materials based on manganese cobalt oxides. Thus, novel insights into the design of high-performance supercapacitors for energy management are provided.     

基于聚多巴胺的氮掺杂碳材料的制备及其电化学性能

多孔碳材料由于高的比表面积、优异的电子传导率、良好的化学稳定性等优点在超级电容器电极材料领域被广泛研究。 碳材料的组成及表面孔结构直接影响其电化学性能,为进一步提高碳材料的电容性能,本文首次以聚多巴胺球为前体,KOH为活化剂,通过高温碳化成功制备了良好电化学性能的氮掺杂多孔碳材料。 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、 X射线粉末衍射(XRD)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)和Raman光谱等对所制备的氮掺杂多孔碳材料进行了形貌及结构组成的表征。 在6 mol/L KOH电解液中, 采用循环伏安、恒电流充放电对多孔碳材料的电化学性能进行了研究。 结果表明,由于双电层电容和赝电容的协同作用,在电流密度为1 A/g时,材料的比电容可达269 F/g,充放电循环1000圈后电容仍可保留初始值的93.5%。     

基于NiCo2O4纳米片电极的非对称混合电容器

The looming global energy crisis and ever-increasing energy demands have catalyzed the development of renewable energy storage systems. In this regard, supercapacitors (SCs) have attracted widespread attention because of their advantageous attributes such as high power density, excellent cycle stability, and environmental friendliness. However, SCs exhibit low energy density and it is important to optimize electrode materials to improve the overall performance of these devices. Among the various electrode materials available, spinel nickel cobaltate (NiCo₂O₄) is particularly interesting because of its excellent theoretical capacitance. Based on the understanding that the performances of the electrode materials strongly depend on their morphologies and structures, in this study, we successfully synthesized NiCo₂O₄ nanosheets on Ni foam via a simple hydrothermal route followed by calcination. The structures and morphologies of the as-synthesized products were characterized by X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller (BET) surface area analysis, and the results showed that they were uniformly distributed on the Ni foam support. The surface chemical states of the elements in the samples were identified by X-ray photoelectron spectroscopy. The as-synthesized NiCo₂O₄ products were then tested as cathode materials for supercapacitors in a traditional three-electrode system. The electrochemical performances of the NiCo₂O₄ electrode materials were studied and the area capacitance was found to be 1.26 C·cm^-2 at a current density of 1 mA·cm^-2. Furthermore, outstanding cycling stability with 97.6% retention of the initial discharge capacitance after 10000 cycles and excellent rate performance (67.5% capacitance retention with the current density from 1 to 14 mA·cm^-2) were achieved. It was found that the Ni foam supporting the NiCo₂O₄ nanosheets increased the conductivity of the electrode materials. However, it is worth noting that the contribution of nickel foam to the areal capacitance of the electrode materials was almost zero during the charge and discharge processes. To further investigate the practical application of the as-synthesized NiCo₂O₄ nanosheets-based electrode, a device was assembled with the as-prepared samples as the positive electrode and active carbon (AC) as the negative electrode. The assembled supercapacitor showed energy densities of 0.14 and 0.09 Wh·cm^-3 at 1.56 and 4.5 W·cm^-3, respectively. Furthermore, it was able to maintain 95% of its initial specific capacitance after 10000 cycles. The excellent electrochemical performance of the NiCo₂O₄ nanosheets could be ascribed to their unique spatial structure composed of interconnected ultrathin nanosheets, which facilitated electron transportation and ion penetration, suggesting their potential applications as electrode materials for high performance supercapacitors. The present synthetic route can be extended to other ternary transition metal oxides/sulfides for future energy storage devices and systems.     

An Overview of Stretchable Supercapacitors Based on Carbon Nanotube and Graphene

The wearable demand of modern electronic devices makes flexible and stretchable energy storage device urgently needed.Stretchable and flexible supercapacitors(SCs) are energy storage devices that provide ultrahigh power density while having long-term durability,high security, and electrochemical stability. Among different SCs electrode materials, CNTs and graphene-based materials exhibit great potential in terms of stretchable SCs due to its ultrahigh electrical conductivity, large specific surface area and good mechanical properties. In this review,the state-of-the-art process and achievements in the field of stretchable SCs enabled by CNTs and graphene are presented, which include the novel design strategy, mechanical and electrochemical properties. The final section highlights current challenges and future perspectives on research in this thriving field.     

Recent advances in the synthesis of non-carbon two-dimensional electrode materials for the aqueous electrolyte-based supercapacitors

Supercapacitors (SCs) with high power density and long cycling span life are demanding energy storage devices that will be an attractive power solution to modern electronic and electrical applications. Numerous theoretical and experimental works have been devoted to exploring various possibilities to increase the functionality and the specific capacitance of electrodes for SCs. Non-carbon two-dimensional (2D) materials have been considered as encouraging electrode candidates for their chemical and physical advantages such as tunable surface chemistry, high electronic conductivity, large mechanical strength, more active sites, and dual non-faradaic and faradaic electrochemical performances. Besides, these 2D materials also play particular roles in constructing highway channels for fast ion diffusion. This concise review summarizes cutting-edge progress of some representative 2D non-carbon materials for the aqueous electrolyte-based SCs, including transition metal oxides (TMOs), transition metal hydroxides (TMHs), transition metal chalcogenides (TMCs), MXenes, metal-organic frameworks (MOFs) and some emerging materials. Different synthetic methods, effective structural designs and corresponding electrochemical performances are reviewed in detail. And we finally present a detailed discussion of the current intractable challenges and technical bottlenecks, and highlight future directions and opportunities for the development of next-generation high-performance energy storage devices.     

静电纺氧化锰复合碳纳米纤维柔性膜的电化学性能

采用一步法静电纺丝技术制备了具有超亲水特性的氧化锰/碳纳米纤维(MnO_x/CNFs)复合柔性膜电极材料,并通过X射线衍射、扫描电子显微镜和透射电子显微镜等对复合材料进行了表征.电化学性能测试结果表明,复合材料的电容性能优于单一材料,醋酸锰质量分数为40%时制得的复合纳米纤维电极(MC-4)在1 A/g电流密度下,于2 mol/L KOH电解液中的比电容高达1112.5 F/g,10 A/g电流密度下循环3000次比容量保持在93.4%,具有很好的稳定性.MnO_x/CNFs复合材料电化学性能增强一方面是由于三维超亲水纤维膜结构有利于电解液的快速浸润渗透,从而极大缩短了传输到材料基质的有效路径;另一方面是由于碳和MnO_x的协同效应,包裹在MnO_x粒子周围的碳层避免了MnO_x在充放电过程中的体积膨胀效应,这2种叠加机制促进了电化学性能的提升.     

High Energy Density Heteroatom (O,N and S) Enriched Activated Carbon for Rational Design of Symmetric Supercapacitors

Carbon-based symmetric supercapacitors (SCs) are known for their high power density and long cyclability, making them an ideal candidate for power sources in new-generation electronic devices. To boost their electrochemical performances, deriving activated carbon doped with heteroatoms such as N, O, and S are highly desirable for increasing the specific capacitance. In this regard, activated carbon (AC) self-doped with heteroatoms is directly derived from bio-waste (lima-bean shell) using different KOH activation processes. The heteroatom-enriched AC synthesized using a pretreated carbon-to-KOH ratio of 1:2 (ONS@AC-2) shows excellent surface morphology with a large surface area of 1508 m² g⁻¹. As an SC electrode material, the presence of heteroatoms (N and S) reduces the interfacial charge-transfer resistance and increases the ion-accessible surface area, which inherently provides additional pseudocapacitance. The ONS@AC-2 electrode attains a maximum specific capacitance (C_sp) of 342 F g⁻¹ at a specific current of 1 Ag⁻¹ in 1 m NaClO₄ electrolyte at the wide potential window of 1.8 V. Moreover, as symmetric SCs the ONS@AC-2 electrode delivers a maximum specific capacitance (C_sc) of 191 F g⁻¹ with a maximum specific energy of 21.48 Wh kg⁻¹ and high specific power of 14 000 W kg⁻¹ and excellent retention of its initial capacitance (98 %) even after 10000 charge/discharge cycles. In addition, a flexible supercapacitor fabricated utilizing ONS@AC-2 electrodes and a LiCl/polyvinyl alcohol (PVA)-based polymer electrolyte shows a maximum C_sc of 119 F g⁻¹ with considerable specific energy and power.     

Interactive effects of pore size control and carbonization temperatures on supercapacitive behaviors of porous carbon/carbon nanotube composites

Porous carbon-based electrodes were prepared by carbonization with poly(vinylidene fluoride) (PVDF)/carbon nanotube (CNT) composites to further increase the specific capacitance for supercapacitors. The specific capacitance, pore size distribution, and surface area of the PVDF/CNT composites were measured, and the effect of the carbonization temperatures was examined. The electrochemical properties were examined by cyclic voltammetry, impedance spectroscopy, and galvanostatic charge-discharge performance using a two-electrode system in TEABF(4) (tetraethylammonium tetrafluoroborate)/acetonitrile as a non-aqueous electrolyte. The highest specific capacitance of ～101 Fg(-1) was obtained for the samples carbonized at 600 °C. The pore size of the samples could be controlled to below 7 nm through the carbonization process. This suggests that micropores make a significant contribution to the specific capacitance due to improved charge transfer between the pores of the electrode materials and the electrolyte.