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首页> 外文学位 >Part I: Electroreductive polymerization of nanoscale solid polymer electrolytes for three-dimensional lithium-ion batteries. Part II: Physical characterization and hydrogen sorption kinetics of solution-synthesized magnesium nanoparticles.
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Part I: Electroreductive polymerization of nanoscale solid polymer electrolytes for three-dimensional lithium-ion batteries. Part II: Physical characterization and hydrogen sorption kinetics of solution-synthesized magnesium nanoparticles.

机译：第一部分：用于三维锂离子电池的纳米级固体聚合物电解质的电还原聚合。第二部分：溶液合成的镁纳米粒子的物理表征和氢吸附动力学。

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摘要

The demand for secondary batteries with longer cycle life and higher power is greater now than ever. Lithium-ion batteries have emerged as the leading technology to store electrochemical energy and power our transportation needs. By employing solution-based nanotemplating methods, new three-dimensional cell configurations can exploit the high-surface area of nanowire array electrodes.The first system explored was the reductive electropolymerization of a zinc vinyl-bipyridine complex [Zn(vbpy)3]2+. The electrochemical synthesis covered the surface of planar and nanowire electrodes. Uniform deposition was observed by XPS and electrochemical "redox-probe" experiments. During the electropolymerization, the potentiodynamic cycle number determined the height of the polymer on the surface of a tin-doped indium-oxide (ITO) electrode. A relationship between the dielectric window and thickness of pZn(vbpy)3 exemplified how the physical characteristics of a polymer electrolyte are closely tied to the electrical characteristics.The second system of interest was the reductive "electrografting" of polymers with vinyl moieties. The reductive electropolymerization of glycidyl methacrylate (GMA) on two-dimensional electrodes was successful, but the conversion to nanowires is on-going research. Solid-state ionic conductivity, tested with a liquid metal eutectic, was observed on Cu2Sb. Ion transport wass induced by soaking the polymer in a 1M LiClO4/PC solution and drying.Copolymerization, an in situ doping method, was required to uniformly distribute Li-ions throughout the solid polymer electrolyte (SPE). The first step towards copolymerization was an in-depth analysis of the homopolymerization of an anionic monomer. Potassium 3-sulfopropyl acrylate (KSPA), soluble in water, was reductively polymerized onto multiple electrode surfaces. The growth was observed electrochemically and spectroscopically (UV-Vis). The reduction potential of the monomer on different electrodes was dependent on the work function of the material, but all depositions of pKSPA were non-uniform and electrically conducting. AFM and XPS measurements taken on polymer-modified ITO electrodes were the basis for the electrochemical island growth of anionic polymers.Electrochemical co-reduction of pGMA with an anionic monomer, pLiMA, uniformly deposited a polymeric layer. A "sweep-step" deposition potential profile successfully incorporated both monomers uniformly. ATR-IR spectroscopy provided some evidence for copolymerization. The curve-fitting analysis of the C 1s and Li 1s XPS HRES scans definitively evidenced the presence of pGMA-co- pLiMA on the surface of Cu2Sb. Variable-temperature solid-state impedance results indicated that the Tg of the copolymer must be lowered to increase the ionic conductivity. If SPEs are to be used in Li-ion batteries, then they must perform as well as common liquid organic electrolytes.However, the decomposition of carbonate-based solvents for Li-ion batteries also offered a route to a solid-state electrolyte. The decomposition of liquid electrolytes commonly used for batteries, such as propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC), produce a solid-electrolyte interface (SEI) layer on the surface of the all battery anode and cathodes. However, capacity retention was improved with the inclusion of the vinylene carbonate (VC) as an additive to the liquid electrolyte.Finding an effective storage medium is a significant challenge facing practical use of hydrogen as a fuel source. Light metal hydrides, such as MgH2, are a proposed solution for the efficient storage of H2 gas. The size of the solution-synthesized magnesium nanocrystals (MgNCs) was controlled by chemical composition of the reducing solution and the concentration of the magnesium precursor, magnesocene. The MgNCs are characterized by XRD and TEM. Extremely fastsorption kinetics is hypothesized to be due to the high-number of defect sites in the crystalline metal-hydride. The activation energy for H/D processes did not significantly change from bulk Mg. (Abstract shortened by UMI.)
机译：现在，对具有更长循环寿命和更高功率的二次电池的需求比以往任何时候都更大。锂离子电池已成为存储电化学能量和满足运输需求的领先技术。通过采用基于溶液的纳米模板方法，新的三维单元结构可以利用纳米线阵列电极的高表面积。首先探索的系统是锌乙烯基联吡啶复合物[Zn（vbpy）3] 2+的还原电聚合。 。电化学合成覆盖了平面电极和纳米线电极的表面。通过XPS和电化学“氧化还原探针”实验观察到均匀沉积。在电聚合过程中，电位动力学循环数确定了掺杂锡的氧化铟（ITO）电极表面上聚合物的高度。介电窗与pZn（vbpy）3的厚度之间的关系说明了聚合物电解质的物理特性如何与电学特性紧密相关。第二个感兴趣的系统是具有乙烯基部分的聚合物的还原“电接枝”。甲基丙烯酸缩水甘油酯（GMA）在二维电极上的还原电聚合是成功的，但正在进行向纳米线的转化研究。在Cu2Sb上观察到用液态金属共晶测试的固态离子电导率。通过将聚合物浸泡在1M LiClO4 / PC溶液中并干燥来诱导离子迁移。需要共聚合（一种原位掺杂方法），以使锂离子均匀分布在整个固体聚合物电解质（SPE）中。迈向共聚的第一步是对阴离子单体均聚的深入分析。溶于水的丙烯酸3-磺基丙酯钾（KSPA）被还原聚合到多个电极表面上。电化学和光谱（UV-Vis）观察到了生长。单体在不同电极上的还原电势取决于材料的功函，但pKSPA的所有沉积均不均匀且导电。在聚合物修饰的ITO电极上进行的AFM和XPS测量是阴离子聚合物电化学岛生长的基础。pGMA与阴离子单体pLiMA的电化学共还原反应均匀沉积了聚合物层。 “扫描步骤”沉积电势曲线成功地将两种单体均匀地结合。 ATR-IR光谱学为共聚提供了一些证据。 C 1s和Li 1s XPS HRES扫描的曲线拟合分析明确证明了Cu2Sb表面上存在pGMA-co-pLiMA。可变温度固态阻抗结果表明，必须降低共聚物的Tg以增加离子电导率。如果要在锂离子电池中使用SPE，则它们必须具有与普通液态有机电解质相同的性能。然而，锂离子电池的碳酸酯类溶剂的分解也为固态电解质提供了一种途径。电池中常用的液体电解质（例如碳酸亚丙酯（PC），碳酸亚乙酯（EC）和碳酸二甲酯（DMC））的分解会在所有电池阳极的表面形成固态电解质界面（SEI）层，阴极。然而，通过在液体电解质中添加碳酸亚乙烯酯（VC）作为添加剂，容量保持能力得到了改善。寻找有效的存储介质是实际使用氢作为燃料源所面临的重大挑战。轻金属氢化物（例如MgH2）是有效存储H2气体的建议解决方案。溶液合成的镁纳米晶体（MgNCs）的大小由还原溶液的化学组成和镁前驱物镁茂的浓度控制。 MgNC的特征在于XRD和TEM。假定极快的吸附动力学是由于结晶金属氢化物中大量的缺陷位。 H / D过程的活化能与块状Mg相比没有显着变化。 （摘要由UMI缩短。）

著录项

  • 作者

    Arthur, Timothy S.;

  • 作者单位

    Colorado State University.;

  • 授予单位 Colorado State University.;
  • 学科 Alternative Energy.Chemistry Inorganic.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 160 p.
  • 总页数 160
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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