超级电容电池

本文比较了超级电容器、锂离子电池和超级电容电池的结构、原理、研究现状和发展前景。超级电容电池的正极具有超级电容器电极的结构和双电层储能机制,负极具有类似锂离子电池负极的结构和快速电化学储能机制。超级电容器和锂离子电池的发展空间都很有限,而作为两者结合的产物的超级电容电池可兼具高比功率、高比能量、高放电电压和长循环寿命的优点,是未来储能电池的发展方向之一,但还面临缺乏具有高分解电压的电解液和高充电电压下电解液中离子枯竭的问题。     

超级电容电池

本文比较了超级电容器、锂离子电池和超级电容电池的结构、原理、研究现状和发展前景。超级电容电池的正极具有超级电容器电极的结构和双电层储能机制,负极具有类似锂离子电池负极的结构和快速电化学储能机制。超级电容器和锂离子电池的发展空间都很有限,而作为两者结合的产物的超级电容电池可兼具高比功率、高比能量、高放电电压和长循环寿命的优点,是未来储能电池的发展方向之一,但还面临缺乏具有高分解电压的电解液和高充电电压下电解液中离子枯竭的问题。     

高能量密度的锂离子混合型电容器

锂离子混合型电容器兼有锂离子电池和超级电容器的优点,在电化学储能领域具有广泛的应用前景. 但其产业化仍存在一系列的基础及工艺方面的问题,具体包括器件结构设计、电极材料筛选、预嵌锂工艺和电解液与电极的界面等. 本文结合作者课题组的研究工作介绍了近年来高能量密度的锂离子混合型电容器的研究进展,内容涉及锂离子电容器正/负极材料的筛选、预嵌锂工艺的优化、内并联结构的锂离子电池型超级电容器复合正极组成材料的调控、隔膜的选择、电解液的组成、以及器件的高/低温性能,分析了锂离子电容器的容量衰减机制,探讨了锂离子电池型超级电容器的储能机制,提出了未来对高能量密度的锂离子混合型电容器研究的展望.     

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.     

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.     

LiTFSI/2-噁唑烷酮电解液与不同微结构碳材料的电化学兼容性

二（三氟甲基磺酸酰）亚胺锂（LiTFSI）与1,3-氮氧杂环戊-2-酮（OZO）形成的离子液体具有良好的物理和电化学性能,表现出宽的液相温度范围和高的离子电导率,可满足超级电容器的应用需求。本文制备的LiTFSI-OZO离子液体体系中,各种离子的结构组成（如自由离子、离子对、积聚离子）及其之间的相互作用对离子液体的电化学性能具有较大的影响,将其作为电解液应用于不同微结构特性（孔径、比表面积等）的炭材料（碳纳米管(CNTs)、中孔活性炭(MEACs)和微孔活性炭(MIACs)）作为电极的电化学双层电容器中,电化学兼容性研究表明,由于中孔活性炭电极材料有最大的比表面积及最适宜的孔径分布,相应的模拟电容具有最高的比容量184.6 F?g-1。该研究表明,对电极材料的微结构特性与离子液体离子尺度进行优化匹配是实现离子液体作为电解液应用于超级电容器的关键。     

隔膜对双电层电容器和混合型电池-超级电容器的电化学性能的影响

隔膜是双电层电容器和混合型电池-超级电容器等电化学储能器件的重要组成元件.本文采用1 mol?L-1四乙基四氟硼酸铵的丙烯碳酸酯电解液制备了基于活性炭的扣式双电层电容器,并采用1 mol?L-1六氟磷酸锂锂离子电解液制备了(LiNi0.5Co0.2Mn0.3O2+活性炭)/石墨体系的混合型电池-超级电容器.研究了不同类型隔膜的物理化学性能,以及其对双电层电容器和混合型电池-超级电容器的电化学性能的影响.四种隔膜分别是无纺布聚丙烯毡、多孔聚丙烯薄膜、Al2O3涂层的聚丙烯薄膜和纤维素纸隔膜.进行了表面形貌、差示扫描量热、电解液吸液量和表观接触角测试表征.电化学测试表明,采用纤维素隔膜的双电层电容器具有最高的比电容和更优的倍率性能,电容器的自放电性能差别不大.而对于混合型电池-超级电容器,采用聚丙烯薄膜和无纺布聚丙烯毡隔膜器件的比容量比其它器件约高20%,且采用纤维素隔膜的器件自放电率最高.     

隔膜对双电层电容器和混合型电池-超级电容器的电化学性能的影响（英文）

隔膜是双电层电容器和混合型电池-超级电容器等电化学储能器件的重要组成元件.本文采用1 mol?L-1四乙基四氟硼酸铵的丙烯碳酸酯电解液制备了基于活性炭的扣式双电层电容器,并采用1 mol?L-1六氟磷酸锂锂离子电解液制备了(LiNi0.5Co0.2Mn0.3O2+活性炭)/石墨体系的混合型电池-超级电容器.研究了不同类型隔膜的物理化学性能,以及其对双电层电容器和混合型电池-超级电容器的电化学性能的影响.四种隔膜分别是无纺布聚丙烯毡、多孔聚丙烯薄膜、Al2O3涂层的聚丙烯薄膜和纤维素纸隔膜.进行了表面形貌、差示扫描量热、电解液吸液量和表观接触角测试表征.电化学测试表明,采用纤维素隔膜的双电层电容器具有最高的比电容和更优的倍率性能,电容器的自放电性能差别不大.而对于混合型电池-超级电容器,采用聚丙烯薄膜和无纺布聚丙烯毡隔膜器件的比容量比其它器件约高20%,且采用纤维素隔膜的器件自放电率最高.     

离子液体在电池中的应用

离子液体由于具有热稳定性好、电导率高、电化学窗口宽、不挥发、不燃烧等特点,其作为新一代功能电解质材料在不同电池体系中的应用成为当前研究的热点.本文对离子液体在电池体系中的最新研究进展作了较为全面的阐述,其中着重介绍了本研究团队近年来面向锂二次电池、超级电容器和燃料电池等不同电化学体系应用研究开发的离子液体基功能电解质材...     

离子液体电解质种类对活性炭电极超级电容器电化学性能的影响

本文将经水蒸气二次活化的椰壳活性炭（W-AC）作为电极材料,选择1-乙基-3甲基咪唑四氟硼酸盐（[EMIM]BF₄）作为电解质,结果表明W-AC电极的比电容量远高于未活化的椰壳活性炭（R-AC）.使用循环伏安、恒电流充放电、交流阻抗等方法研究了不同种类离子液体电解质对超级电容器电化学性能的影响.不同阴阳离子组成的离子液体作为电解质,直接影响超级电容器的电化学性能. 研究表明,由EMIM⁺和BMIM⁺阳离子与BF₄^-、TFSI^-阴离子构成的离子液体电解质较适用于W-AC电极. 其中在[EMIM]BF₄电解质中,单片电极的比电容量可高达153 F·g^-1;在1-丁基-3-甲基-咪唑四氟硼酸盐（[BMIM]BF₄）电解质中电位窗可达3.5V,能量密度可高达57 Wh·kg^-1.本研究对于构筑高性能超级电容器离子液体的选择提供参考,以满足不同应用领域需求.     

Describing the unsuspected advantage of redox ionic liquids applied to electrochemical energy storage

Ionic liquids are a class of solvents widely studied in the literature for various applications. As a subclass of ionic liquids, redox ionic liquids can endow charge exchange properties (electrons transfer) to these electrolytes for electrochemical energy storage. In this review article, we propose to study this family of ionic liquids and suggest a chronological classification. We introduce five generations of redox ionic liquids with different basic compounds such as polyethylene glycol, ferrocene, different linker lengths, TFSI anion, and biredox ionic liquids. The versatility of the redox ionic liquids synthesis will be discussed as well as the fundamental and applied aspects of their use as electrolytes, which have high charge densities. The impact of the redox ionic liquids on the electrochemical mechanisms will be described. We also present how the redox shuttle effect, detrimental to supercapacitors, can be prevented while it can be used to improve lithium-ion batteries.     

Ab initio simulations of liquid electrolytes for energy conversion and storage

Understanding physicochemical properties of liquid electrolytes is essential for predicting and optimizing device performance for a wide variety of emerging energy technologies, including photoelectrochemical water splitting, supercapacitors, and batteries. In this work, we review recent progress and open challenges in predicting structural, dynamical, and electronic properties of the liquids using first-principles approaches. We briefly summarize the basic concepts of first-principles molecular dynamics (FPMD), and we discuss how FPMD methods have enriched our understanding of a number of liquids, including aqueous solutions, organic electrolytes and ionic liquids. We also discuss technical challenges in extending FPMD simulations to the study of liquid electrolytes in more complex environments, including the interface between electrolytes and electrodes, which is a key component in many energy storage and conversion systems.     

面向柔性超级电容器的凝胶电解质研究进展

柔性超级电容器卓越的功率密度和柔性应用能力与可穿戴设备对柔性电源的紧迫需求相吻合,同时具备较大的能量密度提升潜力,使其受到了广泛关注。将水、有机液体、离子液体和导电离子等溶入三维聚合物网络构建导电凝胶作为电解质,不仅简化了柔性超级电容器结构,还通过引入多样的交联方式和合成材料进一步提升其性能,已成为近年备受瞩目的研究方向。本文深入分析并总结了凝胶电解质应用于柔性超级电容器的独特优势及其关键性能优化的方法,包括：调控导电离子含量及传输路径以提高离子电导率;采用双重物理交联和模板化合成策略调节凝胶网络结构以改善机械性能;引入有机液体、离子液体等溶剂限制冰晶形成,从而拓宽工作温度范围。然而,凝胶电解质在柔性超级电容器应用中仍然面临一系列挑战,包括生物相容性不足、电极/电解质界面兼容性弱以及合成材料的环保性不佳。未来研究需进一步解决上述问题,以实现凝胶电解质在柔性超级电容器中的高效应用。     

Redox-active electrolyte supercapacitors using electroactive ionic liquids

Here we present redox ionic liquid supercapacitors (RILSCs) which use electrolytes made from ionic liquids modified with an electroactive function to increase the energy density of activated carbon electrodes via faradaic reactions. More specifically, two different ionic liquids were made by modifying either the imidazolium cation or the bis(trifluoromethanesulfonyl)imide anion with ferrocene in order to determine the importance of the electroactive ion's polarity. The functionalization of an ionic liquid with ferrocene led to high concentrations of redox moieties in the electrolyte (2.4 M) and a large maximum operating voltage (2.5 V). An energy density of up to 13.2 Wh per kg (both electrodes) was obtained which represents an 83% increase vs. the unmodified ionic liquid. When the ionic liquid's anion is modified with ferrocene, the self-discharge at the positive electrode is fully suppressed due to the deposition of a film on the electrode. The results presented herein demonstrate that electroactive ionic liquids constitute a promising alternative to conventional solute in solvent electrolytes found in energy storage devices, and are particularly well-suited for redox-active electrolyte supercapacitors.     

Superior performance for lithium-ion battery with organic cathode and ionic liquid electrolyte

Organic small structure quinones go with ionic liquids electrolytes would exhibit ultrastable electrochemical properties.In this study,calix[6]quinone(C6Q) cathode was matched with ionic liquid electrolyte Li[TFSI]/[PY13][TFSI](bis(trifluoromethane)sulfonimide lithium salt/N-methyl-N-pro pylpyrrolidinium bis(trifluoromethanesulfonyl)amide) to assemble lithium-ion batteries(LIBs).The electrochemical performance of LIBs was systematically studied.The capacity retention rates of C6Q through 1000 cycles at current densities of 0.2 C and 0.5 C were 70% and 72%,respectively.At 5 C, the capacity was maintained at 190 mAh g^-1 after 1000 cycles,and 155 mAh g^-1 even after 10,000 cycles,comparable to inorganic materials.This work would give a big push to the practical process of organic electrode materials in energy storage.     

Recent Progress in Organic–Inorganic Composite Solid Electrolytes for All-Solid-State Lithium Batteries

Conventional lithium-ion batteries, with flammable organic liquid electrolytes, have serious safety problems, which greatly limit their application. All-solid-state batteries (ASSBs) have received extensive attention from large-scale energy-storage fields, such as electric vehicles (EVs) and intelligent power grids, due to their benefits in safety, energy density, and thermostability. As the key component of ASSBs, solid electrolytes determine the properties of ASSBs. In past decades, various kinds of solid electrolytes, such as polymers and inorganic electrolytes, have been explored. Among these candidates, organic–inorganic composite solid electrolytes (CSEs) that integrate the advantages of these two different electrolytes have been regarded as promising electrolytes for high-performance ASSBs, and extensive studies have been carried out. Herein, recent progress in organic–inorganic CSEs is summarized in terms of the inorganic component, electrochemical performance, effects of the inorganic ceramic nanostructure, and ionic conducting mechanism. Finally, the main challenges and perspectives of organic–inorganic CSEs are highlighted for future development.     

离子液体在制备金属氧化物纳米材料中的应用

总结了近年来在离子液体中制备金属氧化物纳米材料的新方法以及离子液体在金属氧化物纳米材料制备方面的应用及发展趋势.目前,对于制备纳米金属氧化物,离子液体主要是作为电解液、表面活性剂;其未来的发展趋势是离子热合成和集模板-溶剂-反应物于一身的离子液体反应.     

Nonflammable nonaqueous electrolytes for lithium batteries

As the energy density of state-of-the-art lithium (Li)-ion batteries (LIBs) increases, the safety concern of LIBs using liquid electrolytes is drawing increasing attention. Flammability of electrolytes is a critical link of the overall safety performance of LIBs and Li metal batteries. For this reason, intensive efforts have been devoted to suppressing the flammability of liquid electrolytes. In this short review, the common approaches to reduce the flammability of the nonaqueous liquid electrolytes will be summarized. The advantages and limitations of these approaches will also be discussed.     

Recent progress of composite solid polymer electrolytes for all-solid-state lithium metal batteries

In comparison with lithium-ion batteries (LIBs) with liquid electrolytes, all-solid-state lithium batteries (ASSLBs) have been considered as promising systems for future energy storage due to their safety and high energy density. As the pivotal component used in ASSLBs, composite solid polymer electrolytes (CSPEs), derived from the incorporation of inorganic fillers into solid polymer electrolytes (SPEs), exhibit higher ionic conductivity, better mechanical strength, and superior thermal/electrochemical stability compared to the single-component SPEs, which can significantly promote the electrochemical performance of ASSLBs. Herein, the recent advances of CSPEs applied in ASSLBs are presented. The effects of the category, morphology and concentration of inorganic fillers on the ionic conductivity, mechanical strength, electrochemical window, interfacial stability and possible Li⁺ transfer mechanism of CSPEs will be systematically discussed. Finally, the challenges and perspectives are proposed for the future development of high-performance CSPEs and ASSLBs.