基于金属氧化物的赝电容器

电极是电化学超级电容器的重要组成部分,电极材料是决定超级电容器性能的最重要因素。金属氧化物电极材料兼有双电层电容和准电容性质,其比电容远远大于活性炭材料表面的双电层电容,基于金属氧化物电极材料的超级电容器具有使用寿命长、维护简单等优点,是一种新型、高效、实用的能量存储装置,引起研究者的广泛兴趣。本文综述了基于金属氧化物电极材料的赝电容器的储能原理、类型和性能的研究现状,并展望了其发展前景。     

电化学超级电容器电极材料的研究进展

回顾了电化学超级电容器电极材料的研究进展，并对不同电极材料的储能原理和性能特点进行了简要的阐述。参考文献29篇。     

超级电容器用镍锰基二元金属氧化物电极材料

赝电容电容器相比于双电层电容器拥有更高的比容量(大约10~100倍),由于在充电/放电过程中法拉第反应同时在电极材料表面和内部发生。因此,会产生更多电子,拥有更大的比容量。目前,赝电容电极材料的研究主要集中在金属氧化物和导电聚合物。镍锰基金属氧化物具有较高的理论比容量、成本低、无毒、环境友好等优点,但是其实际的电化学性能远低于理论值。因此,为了提升材料的电化学表现,研究者提出许多有效的策略,例如:制备不同种类金属氧化物作为电极材料;采用不同的工艺制备高比表面积的材料以及不同材料之间的复合产生协同作用等。本文综述了镍锰基二元金属氧化物(NiMnO₃、NiMn₂O₄和Ni₆MnO₈)作为赝电容电极材料在超级电容器上的应用进展,同时结合目前研究方法进一步提出未来金属氧化物电极材料方面的发展方向,为继续深入研究提供一定的指导作用。     

电化学电容器中二氧化锰电极材料研究进展

本文在简介MnO2电极材料的性质和特点基础上,重点介绍近5年来国内外有关MnO2电极材料在合成及电化学电容器应用领域中的最新进展,及未来可能的发展方向。     

电化学电容器电极材料超细MnO2的制备及表征

高性能的电化学电容器具有极其重要和广阔的应用前景(1)。以RuO2等贵重金属氧化物为电极材料的电化学电容器已应用于多个领域(2),但昂贵的价格限制了它们更加广泛的应用。有些廉价金属氧化物也具有一定的氧化还原准电容,如Co3O4、NiO和MnO2等(1,3 6)。二氧化锰价格低廉,资源丰富,电化学性能好,其作为电化学电容器的活性材料具有更大的应用前景和价值。本文采用K2S2O8氧化MnSO4·H2O制得超细MnO2,并通过XRD、TEM和SEM测试对其进行表征,并研究了其在0 5mol/LNa2SO4水溶液中的循环伏安性能、恒流充放性能以及电容稳定性能。1…     

超级电容器用石墨烯/金属氧化物复合材料

超级电容器是一种具有高功率密度和长循环寿命的新型储能装置,碳材料、金属氧化物和导电聚合物是常见的三种超级电容器电极材料。在石墨烯/金属氧化物复合材料中,石墨烯和金属氧化物可以发挥各自的优点,结合石墨烯优异的循环稳定性能和金属氧化物的高容量特性,纳米复合材料的综合性能可以得到很大地提升。因此,石墨烯/金属氧化物复合物的研究是超级电容器领域的热点研究方向之一。本文以金属氧化物的种类、石墨烯的结构和复合物的制备方法为线索,综述了国内外应用于超级电容器方面的石墨烯/金属氧化物复合材料的研究进展,归纳总结出与石墨烯复合最优的金属氧化物类型和制备方法,并进一步对该类复合材料的发展趋势进行了展望。     

V2O5/C电化学电容器有机电解液的性能研究

以偏钒酸铵为反应原料,采用液相沉淀法制备出不定型V2O5电极材料.以V2O5为正极,石墨为负极,分别选用1.0 mol/L LiClO4/EC+DMC、1.0 mol/L LiPF6/EC+DEC+DMC、1.6 mol/L Et4NBF4/AN 3种有机电解液组成不对称电化学电容器,恒流充放电、循环伏安和交流阻抗等测试该模拟电容器,如以1.0 mol/LLiClO4/EC+DMC作电解液则具有良好的循环性能和较小的阻抗,且在500 mA/g电流密度下比能量达到8.4Wh/kg,充放电效率达98%.     

基于碳材料的超级电容器电极材料的研究

超级电容器作为一种新型的能源存储装置,因为其比容量大、充放电速度快、循环寿命长等优点,在储能领域引起了极为广泛的关注。电极材料是决定超级电容器性能的核心因素,其中,常用的超级电容器电极材料主要有如下三类:碳基材料、金属氧化物及氢氧化物材料和导电聚合物材料。本文综述了超级电容器的工作原理并详细介绍了基于碳材料及其二元、三元复合体系的电极材料的研究进展。     

电化学电容器连续模型的建立与研究进展

电化学电容器（超级电容器）是一种兼具高能量密度和高功率密度的新型储能元件,它既具有传统电容器大电流快速充放电的特性,又具有蓄电池高储能密度的特性. 近几年,电化学电容器储能机理的研究和纳米结构电极复合材料的合成不断取得新突破,超级电容器的电化学性能得到了显著的提高. 为了更好地解析电化学电容器的工作特性,建立描述电容器内部浓度分布和电场的物理模型是一项非常重要的研究方法. 本文首先介绍电化学电容器理论基础,并论述近几年电化学电容器连续模型研究进展,最后阐述连续模型进一步发展的前景和挑战.     

聚苯胺在电化学电容器中的应用

The performance of a newly designed, polyaniline activated carbon, hybrid electrochemical capacitor was evaluated. The polyaniline was prepared by the chemical oxidation/polymerization process. The capacitor was assembled by using polyaniline as a positive electrode and an activated carbon as a negative electrode respectively. From a cyclic voltammograms test, a specific capacitance of 420 F/g was obtained for polyaniline electrode. The cycle life of the cell is proved to be more than 1000 times by the Galvanostatic charge and discharge test. Values for the specific energy and real specific power of 15.5 Wh/kg and 2.8 W/g, respectively, are demonstrated for a cell voltage between 0.0 and 1.4 V. The max specific power for the hybrid capacitor amounts to 20.4 W/g.     

铝代α-Co（OH）2的制备及其电化学性能

采用化学共沉淀方法制备了Co-Al双金属氢氧化物,用红外光谱对所制样品的成分进行分析;用X射线衍射和场发射扫描电子显微镜表征产物的结构和形貌;用循环伏安、恒电流充放电等测试方法对Co/Al摩尔比为9∶1、8∶2和7∶3的铝代α-Co(OH)2的电化学性能进行研究。测试表明,Co/Al摩尔比为8∶2的铝代α-Co(OH)2具有最佳的电容性能,单电极比电容可达1180F/g,并且在1A/g电流密度下循环500周后,比电容仍能保持91%,有望成为电化学电容器的电极材料。     

基于金属氧化物材料的二氧化碳电催化还原

The CO₂ level in the atmosphere has been increasing since the industrial revolution owing to anthropogenic activities. The increased CO₂ level has led to global warming and also has detrimental effects on human beings. Reducing the CO₂ level in the atmosphere is urgent for balancing the carbon cycle. In this regard, reduction in CO₂ emission and CO₂ storage and usage are the main strategies. Among these, CO₂ usage has been extensively explored, because it can reduce the CO₂ level and simultaneously provide opportunities for the development in catalysts and industries to convert CO₂ as a carbon source for preparing valuable products. However, transformation of CO₂ to other chemicals is challenging owing to its thermodynamic and kinetic stabilities. Among the CO₂ utilization techniques, electrochemical CO₂ reduction (ECR) is a promising alternative because it is generally conducted under ambient conditions, and water is used as the economical hydrogen source. Moreover, ECR offers a potential route to store electrical energy from renewable sources in the form of chemical energy, through generation of CO₂ reduction products. To improve the energy efficiency and viability of ECR, it is important to decrease the operational overpotential and maintain large current densities and high product selectivities; the development of efficient electrocatalysts is a critical aspect in this regard. To date, many kinds of materials have been designed and studied for application in ECR. Among these materials, metal oxide-based materials exhibit excellent performance as electrocatalysts for ECR and are attracting increasing attention in recent years. Investigation of the mechanism of reactions that involve metallic electrocatalysts has revealed the function of trace amount of oxidized metal species—it has been suggested that the presence of metal oxides and metal-oxygen bonds facilitates the activation of CO₂ and the subsequent formation and stabilization of the reaction intermediates, thereby resulting in high efficiency and selectivity of the ECR. Although the stability of metal oxides is a concern as they are prone to reduction under a cathodic potential, the catalytic performance of metal oxide-based catalysts can be maintained through careful designing of the morphology and structure of the materials. In addition, introducing other metal species to metal oxides and fabricating composites of metal oxides and other materials are effective strategies to achieve enhanced performance in ECR. In this review, we summarize the recent progress in the use of metal oxide-based materials as electrocatalysts and their application in ECR. The critical role, stability, and structure-performance relationship of the metal oxide-based materials for ECR are highlighted in the discussion. In the final part, we propose the future prospects for the development of metal oxide-based electrocatalysts for ECR.     

Electrochemical Sensor Platforms Based on Nanostructured Metal Oxides,and Zeolite‐Based Materials

Electrochemical sensors have drawn significant attention over the last couple of decades because of their ability to improve detection of organic and inorganic analytes found in the field of biotechnology, environmental sciences, medicine, and food quality control. This personal account summarizes the state‐of‐art research carried out in the construction and evaluation of nanostructured metal oxides and zeolite based electrochemical sensors. Metal oxides and zeolite‐based nanomaterials have many unique and extraordinary properties such as tunable redox activity, surface functionalization ability, optimum conductivity, large surface area, biocompatibility and so forth. In this personal account, the current advances in electrochemical sensor applications of metal oxides, zeolite‐based nanomaterials, and their nanocomposites are described for the single and simultaneous determination of organic & inorganic contaminants present in water bodies, physiological bio‐molecules present in human blood & urine samples, and organic contaminants present in food materials.Moreover, concluding section focuses discussion on the future developments and applications of these materials in various emerging technologies.     

Molecular Organometallic Chemistry on Surfaces: Reactivity of Metal Carbonyls on Metal Oxides

Metal carbonyls react on metal oxide surfaces to give a wide range of structures analogous to those of known compounds. The reactions leading to formation of surface-bound metal carbonyls are explained by known molecular organometallic chemistry and the functional group chemistry of the surfaces. The reaction classes include formation of acid-base adducts as the oxygen of a carbonyl group donates an electron pair to a Lewis acidic center; nucleophilic attack at CO ligands by basic surface hydroxyl groups or O^2? ions; ion-pair formation by deprotonation of hydrido carbonyls to give carbonylate ions; interaction of bifunctional complexes with surface acid-base pair sites such as [Mg^2⊕O^2?]; and oxidative addition of surface hydroxyl groups to metal clusters. The reactions of surface-bound organometallic species include redox condensation and cluster formation on basic surfaces (paralleling the reactions in basic solution) as well as oxidation of mononuclear metal complexes and oxidative fragmentation of metal clusters by reaction with surface hydroxyl groups. Most supported metal carbonyls are unstable at high temperatures, but some, including osmium carbonyl cluster anions on the basic MgO surface, are strongly stabilized in the presence of CO and are precursors of catalysts for CO hydrogenation at 550 K.     

纳米纤维聚苯胺在电化学电容器中的应用

采用脉冲电流方法（PGM）合成了具有纳米纤维结构的导电聚苯胺（PANI）.扫描电子显微镜对膜层观察表明, PANI膜是由直径约为100 nm的掺杂态聚苯胺纤维交织而成.以纳米纤维状聚苯胺组成电化学电容器,研究了其电化学电容性能,并与恒电流方法（GM） 制备的颗粒状PANI电容器性能进行了比较.结果表明,在相同的沉积电量下,PGM制备的纳米纤维状PANI电化学电容器比颗粒状PANI电化学电容器具有更大的电容容量,其电化学电容器的比电容可高达699 F•g－1,能量密度为54.6 Wh•kg－1.并且该电化学电容器具有良好的充放电性能和循环寿命.     

Ba—Pb—O和Bi—Pb—O的电化学合成和表征

本文研究了用电化学方法在水溶液中合成铅基氧化物Ｂａ－Ｐｂ－Ｏ和Ｂｉ－Ｐｂ－Ｏ的方法，并采用ＸＰＳ，ＸＲＤ和ＥＤＸ对电合成产物进行了表征。     

金属氧化物催化生物质衍生羧酸酮基化研究进展

从可再生的木质纤维素生物质制备液体燃料受到越来越多的关注.有机羧酸是生物质解聚生物油的重要成分,使得生物油具有酸性、腐蚀性和不稳定性.因而,羧酸的去除十分关键.酮基化反应将两分子羧酸转化为酮、二氧化碳和水,不使用氢气的情况下高效脱氧且增加碳链长度.此外,生成的酮为重要化学品.目前酮基化反应的机理和活性位的研究还存在争论.因酮基化反应过程生成的中间产物不同（如β-酮酸、酮烯、羧化物、酰基碳正离子等）,研究者们提出了不同的反应机理,如β-酮酸机理和酮烯机理.酮基化反应属于结构敏感性反应,因此金属氧化物表面结构的不同会导致酮基化反应活性不同.酸碱位协同作用在酮基化反应过程中是必不可少的,同时氧空位可以提高酮基化反应的活性.本综述重点从酮基化反应机理、金属氧化物的表面结构、酸碱性及氧化还原性方面对酮基化反应进行了评述,并对其进行了展望.     

电化学混合电容器用新型聚吡咯/介孔碳纳米复合电极

采用介孔碳CMK-3作为载体,通过化学原位聚合的方法制备出一种新型的聚吡咯/介孔碳(PPy-CMK-3)纳米复合材料.将该纳米复合材料作为正极,配以介孔碳CMK-3为负极和1.0mol·L-1NaNO3中性电解液,组装成为电化学混合电容器.电化学测试表明:在5.0mA·cm-2电流密度和1.4V充放电电位条件下,其放电比容量达57F·g-1,电容器功率密度为2.5×102W·kg-1,能量密度达17Wh·kg-1.当电流密度从5.0mA·cm-2增加至50mA·cm-2时,电容器的容量保持率在80%以上,显示高倍率充放电特性优异.此外,聚吡咯-介孔碳/介孔碳电化学混合电容器易活化,并具有优异的充放电效率和良好的循环稳定性能.     

柔性超级电容器电极材料与器件研究进展

超级电容器,也称电化学电容器,它具有比锂离子电池更高的功率密度和更长的循环寿命,与此同时,其能量密度也高于传统的电介质电容器,因此成为了一类具有很大应用前景的能量储存设备。随着人们对智能电子设备性能要求的提高,各类柔性可穿戴电子设备相继出现,柔性超级电容器作为一类便携式能量储存设备也受到了许多研究者的关注。在持续的研究中,二维平面结构的柔性超级电容器得到较大发展并日益成熟,与此同时,随着对柔性电子设备可穿戴性能要求的提高,一维纤维结构的柔性超级电容器应运而生,并且得到了初步发展。本文首先介绍了超级电容器的储能原理和重要性能的评估方法;接着,重点概述了二维平面结构和一维纤维结构两类柔性超级电容器器件结构和电极材料的研究进展;最后,总结了两类柔性超级电容器仍然存在并亟待解决的问题以及未来发展所面临的关键技术挑战,期望能为柔性超级电容器的研究提供参考和借鉴。