超疏水表面一般是指与水的接触角大于150°的表面。人们对超疏水表面的认识，主要来自植物叶—荷叶表面的“自清洁”现象。研究认为，材料表面合适的粗糙度和低表面能物质修饰是实现超疏水的两个必要条件。通常，一步方法无法同时实现这两个条件，所以，超疏水表面，尤其是金属表面的超疏水制备，通常需要两步法，一，使其粗糙；二，使其表面能降低。科研人员为了实现上述两个步骤，分别设计出众多的技巧和途径。比如，为了实现粗糙度，可以采用电沉积、腐蚀法、模版法等等；为了实现低表面能，可以采用浸泡、溅射、或者蒸镀低表面能物质等等。总之，金属表面的超疏水，两步方法往往不可避免，因此，如何设计一步方法实现金属表面的超疏水成为本研究的目标。 电沉积Ni镀层多在水性电解液中，而如果采用离子液体作为电解液的溶剂，那么可以很容易实现大气环境下的高温电沉积，而温度的效应可以赋予沉积镀层新的特性。本研究惊奇的发现，高温下直接电沉积出来的Ni镀层表现出超疏水的特性，而且可以通过改变沉积波形对沉积薄膜的表面形貌进行调控。 Please see: One-Step Fabrication of Nanostructured Ni Film with Lotus Effect from Deep Eutectic Solvent, Langmuir, 2011, 27, 10132–10140 ., DOI: 10.1021/la200778a, http://pubs.acs.org/doi/abs/10.1021/la200778a
Journal of Power Sources Article in Press, Accepted Manuscript - Note to users doi:10.1016/j.jpowsour.2011.02.041 | How to Cite or Link Using DOI Copyright 2011 Published by Elsevier B.V. Permissions Reprints Capacitance Improvement of Supercapacitor Active Material Based on Activated Carbon Fiber Working with a Li-ion Containing Electrolyte Tsutomu Takamura a , , , Youh Sato b and Yuichi Sato b a Department of Applied Chemistry, Harbin Institute of Technology, West Dazhi Road, Harbin 150001, China b Department of Applied Chemistry, Kanagawa University, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan Received 10 August 2010; revised 2 February 2011; accepted 17 February 2011. Available online 24 February 2011. Abstract In an attempt to provide a favorable active material of Li+ supercapacitor for HEV use, we modified the surface of an activated carbon fiber felt by coating with some transition metal oxides after mild-oxidation treatment. Major source of enhancing capacitance is attributed to be due to the nano-ionics mechanism proposed by Maier and coworkers. Cyclic voltammetry and constant current charge-discharge performance were examined for the surface modified samples in view of power capability. The oxides of Ag, Cu, Pd, and Sn were found effective to enhance the capacitance and high rate charge/discharge performance. The cycleability test was performed as well. Key words: Supercapacitor active material; Activated carbon fiber; Capacitance enhancement; Surface modification; Coating of transition metal oxide;Nano-ionics mechanism
口述形式 随想随写 锂空气电池的发展现在应该是进入了一个群雄并起的时段了 所以我们要思索的是： 1、锂空电池原理； 2、模块组成及其相应挖掘空间； 3、新型结构及原创想法的思索来源机理； 4、其他化学电源 的 并行借鉴发展。 *锂空气不外乎由氧还原催化剂、碳基正极载体材料、隔膜、电解质或电解液组成，那么需要的是 高级电催化机理相关知识、碳基材料的合成和认识基础和电解系列有机知识了； *但是现阶段最可能新潜力的新型电池结构的开发，当然还有新结构（包括1、电解质组态——是否也是聚合物复合隔膜处理，或是常规膜和电解液及其添加剂问题了；2、电极结构上的改进——使之更透气、更使得氧化还原的持续——碳和催化剂的分布复合问题——使得保证反应的不中止）那么以后我想，在材料方面就是这面最有得可为了——如何实现有效的分布和复合了； *——其实大家都知道的成功案例就是日本的王永刚（复旦夏永姚老师的博士）做的水系和有机系的复合电池——严格来说不是锂空气电池了：一边不变，另一边变得还算不错的文章哗啦啦的出来——但是给我们的启示应该是去寻找两端正负极的材料构成的思路—— 正负极要再元素周期表的左右两侧寻求最合适的反应元素——如果H能进来（其实就是燃料电池的模型了），那当然能量比是绝高的了，再者前些阵子的NaS，LiS，Mg空气电池其实就是为我们选择元素做了方向指示。。。 *当然这边不得不说的是，JACS新出来的贵金属PtAu复合的协同效应催化剂也是给我们指了条方向思路——复合负载——分布又兼起效。。。 *还有一个就是，参照传统锂电池发展的模式或有些粗略的启示：是否如新近的NL上的文章有机物直接负载在活性物质上呢？——那么也就是说如果将正极的复合材料在多孔或其他材料上直接复合处理成聚合物电解质在一起，可保证反应的路径效率以及循环倍率效率呢。。。 *胡言一句 多学科的交叉融合 将成就你我这一批人 在新兴方向的 。。。 本弱弱的博客将持续记录原创心得体会——主要方面在 成型商品电池（18650为主）的设计，传统锂电负极的构想研究，行业需求关于我们同行将来出路规划 三方面展开胡言乱语 以供彼此交流。 附注：（from http://en.wikipedia.org/wiki/Lithium_air_battery 维基百科） A lithium-air battery is a battery in which a lithium anode is electrochemically coupled to atmospheric oxygen through an air cathode . During discharge, lithium cations flow from the anode through an electrolyte and combine with oxygen at the cathode (typically consisting of porous carbon ) to form lithium oxide Li 2 O or lithium peroxide Li 2 O 2 which is inserted in the cathode; this is coupled to the flow of electrons from the battery's anode to the cathode through a load circuit. Lithium air batteries have higher energy density than lithium ion batteries because of the lighter cathode and the fact that oxygen is freely available in the environment and does not need to be stored in the battery. Theoretically, with oxygen as an unlimited cathode reactant, the capacity of the battery is limited by the Li anode. Lithium air batteries are currently under development and are not yet commercially available. 欢迎留言交流 放假回家 新年快乐哈
UBE targeting functional electrolytes for automotive applications 作者： Mike Millikin UBE Industries, which last week announced a new electrolyte development center for large Li-ion batteries in Europe ( earlier post ), is targeting the development of functional electrolytes for Li-ion batteries for automotive applications. At the Advanced Automotive Battery Conference (AABC) in Pasadena this week, Yoshihiro Ushigoe, manager of the electrolyte development team for UBE provided an overview of the company’s efforts. The electrolyte is one of the four main components of a Li-ion battery, the other three being the separator, the cathode, and the anode. In his AABC tutorial on battery materials, Prof. Martin Winter from the University of Muenster noted that the electrolyte is a key system component, and should be treated as such. UBE has been a leader in the development of the concept of functional electrolytes, reporting on them for the first time in 1999. Functional electrolytes are small amounts of chemical additives mixed in a highly-purified electrolyte base to introduce a specific high-performance functionality, or role, in the electrolyte system. Due to the high purity of UBE’s base electrolyte, electrolyte decomposition itself is inhibited, UBE notes. Consequently, a small amount of additive is deliberately decomposed on the anode surface to produce the solid electrolyte interphase (SEI) to improve battery performance. Various compounds are already in use as electrolyte additives, including agents for anode passivation (SEI), cathode protection (cathode SEI), overcharge protection, wettability improvement, flame retardation, trapping of undesired components, and improving electrolyte conductivity, among many others. Novolyte functional additives for electrolytes In a separate presentation at AABC, Martin Payne from Novolyte presented results showing that Novolyte’s new D5 additive shows equal or better performance in cell testing at equal additive levels and is an acceptable replacement for the industry stand-by vinylene carbonate (VC). Payne also noted that several approaches can be taken to solve high temperature challenges, each dependent on cell chemistry and specific electrolyte components. Novolyte is also developing a series of new additives that reduce flammability and enhance safety. The NF additive also sow improved performance in cycling, capacity retention, rate performance and storage. In 2007, in a paper in the Journal of the Electrochemical Society , UBE researchers reported a novel type of anode additive containing a triple-bonded moiety, which produces a thin and dense SEI, improving battery performance, especially in cycleability. A practical electrolyte may contain more than one additive. In a subsequent paper published in 2008, the UBE researchers observed a novel and unique effect of an additive combination. The combination of triple-bonded compounds and double-bonded compounds showed much improved battery performance, especially in cycleability and gas evolution, than the case when they are singly used. In this specific case, the team suggested that the higher battery performance of the combination effect resulted not only from the thin and dense SEI on the negative electrode but also from the positive electrode surface co-polymerized film produced by the synergetic decomposition of the additives. UBE is now focusing on the development of an electrolyte able to be utilized at a higher working voltage (for higher capacities) and over a wider working temperature. Complicating matters, lithium-ion batteries (LIBs) at higher working voltages or temperatures have inherent problems of property degradation or gas evolution. Resources Koji Abe, Takashi Hattori, Kazuyuki Kawabe, Yoshihiro Ushigoe, and Hideya Yoshitake (2007)Functional Electrolytes J. Electrochem. Soc. 154, A810 doi: 10.1149/1.2746570 Koji Abe, Kazuhiro Miyoshi, Takashi Hattori, Yoshihiro Ushigoe, Hideya Yoshitake (2008) Functional electrolytes: Synergetic effect of electrolyte additives for lithium-ion battery, Journal of Power Sources , Volume 184, Issue 2, Pages 449-455 doi: 10.1016/j.jpowsour.2008.03.037 .
Novel lithium salt improves high-temperature resilience in Li-ion cells 作者： Mike Millikin Researchers at Huazhong University of Science and Technology in China are exploring the use of a novel lithium salt, lithium (fluorosulfonyl)(nonafluorobutanesulfonyl)imde (LiFNFSI), as conducting salt in the electrolyte to improve the high-temperature resilience of lithium-ion cells. It shows better thermal stability than LiPF6. The electrolyte having 1.0 M LiFNFSI in a mixture of ethylene carbonate (EC)/ethyl methyl carbonate (EMC) (3:7, v/v) shows high conductivity comparable to LiClO4, good electrochemical stability, and does not corrode aluminum. At both room temperature (25 °C) and elevated temperature (60 °C), the graphite/LiCoO2 cells with LiFNFSI exhibit better cycling performances than those with LiPF6. Particularly, at 60 °C, the capacity fading rate of the LiFNFSI-based cell without any additive is 37% after 100 cycles, while the cell with LiPF6 fails rapidly. These outstanding properties of LiFNFSI make it an attractive candidate to overcome the rapid capacity fading of lithium-ion batteries at elevated temperatures. —Han et al. Resources Hongbo Han, Jun Guo, Daijun Zhang, Shaowei Feng, Wenfang Feng, Jin Nie, Zhibin Zhou (2011) Lithium (fluorosulfonyl)(nonafluorobutanesulfonyl)imide (LiFNFSI) as conducting salt to improve the high-temperature resilience of lithium-ion cells. Electrochemistry Communications , In Press doi: 10.1016/j.elecom.2010.12.030
标签: 电解液
