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Heterogeneous ordered mesoporous carbon/metal oxide composites for the electrochemical energy storage.

机译：用于电化学储能的非均质有序介孔碳/金属氧化物复合材料。

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摘要

The combination of high electronic conductivity, enhanced ionic mobility, and large pore volume make ordered mesoporous carbons (OMCs) promising scaffolds for active energy storage materials. However, mesoporous structures and material morphology need to be more thoroughly addressed. This dissertation discusses the effects of mesoporous structures and material morphologies on the electrochemical performance of OMC/Fe2O3 composites. In the first approach, Fe2O3 was embedded into 1D cylindrical (FDU-15), 2D hexagonal (CMK-3), and 3D bicontinuous (CMK-8) symmetries of mesoporous carbons. These materials were used as supercapacitors for a systematic study of the effects of mesoporous architecture on the structure stability, ion mobility, and performance of mesoporous composite electrodes. The results show that the CMK-3 and CMK-8 synthesized by hard template method can provide high pore volume, but the instability of their mesostructures hinders the total electrode performances upon oxide impregnation. In contrast, the FDU-15 from the soft template method can provide a stable mesostructure. However, it contains much smaller pore volume and surface area, leading to limited metal oxide loading and electrode capacitance. Based on these results, anodized aluminum oxide (AAO) and triblock copolymer F127 are used together as hard and soft templates to fabricate ordered mesoporous carbon nanowires (OMCNW) as a host material for Fe2O3 nanoparticles. The synergistic effects in the dual template strategy provide a high pore volume and surface area, and the structure remains stable even with high metal oxide loading amounts. Additionally, the unique nanowire morphology and mesoporous structure of the OMCNW/Fe2O3 facilitate high ionic mobility in the composite, leading to a large capacitance with good rate capability and cycling stability. I further evaluated this OMCNW/Fe2O3 as a lithium-ion battery (LIB) anode, which showed that the porous symmetry, material morphology, and structure stability are even more important in the rate and cycling performances of LIBs. This work helps further the understanding and optimization of porous structures and morphologies of heterogeneous composites for next generation electrochemical energy storage materials.
机译：高电子电导率，增强的离子迁移率和大孔体积的结合使有序介孔碳（OMC）成为用于活性能量存储材料的有前途的支架。但是，介孔结构和材料形态需要更彻底地解决。本文讨论了介孔结构和材料形态对OMC / Fe2O3复合材料电化学性能的影响。在第一种方法中，将Fe2O3嵌入介孔碳的1D圆柱（FDU-15），2D六角形（CMK-3）和3D双连续（CMK-8）对称结构中。这些材料用作超级电容器，用于系统研究介孔结构对介孔复合电极的结构稳定性，离子迁移率和性能的影响。结果表明，采用硬模板法合成的CMK-3和CMK-8可以提供较大的孔体积，但介孔结构的不稳定性阻碍了氧化物浸渍后的整体电极性能。相反，来自软模板方法的FDU-15可以提供稳定的介观结构。然而，它包含的孔体积和表面积要小得多，导致有限的金属氧化物负载和电极电容。基于这些结果，阳极氧化氧化铝（AAO）和三嵌段共聚物F127一起用作硬模板和软模板，以制造有序介孔碳纳米线（OMCNW）作为Fe2O3纳米粒子的主体材料。双模板策略中的协同效应提供了高的孔体积和表面积，即使在高金属氧化物负载量的情况下，结构也保持稳定。此外，OMCNW / Fe2O3独特的纳米线形态和中孔结构促进了复合物中的高离子迁移率，从而产生了具有良好倍率能力和循环稳定性的大电容。我进一步评估了该OMCNW / Fe2O3作为锂离子电池（LIB）的阳极，结果表明，多孔对称性，材料形态和结构稳定性在LIB的速率和循环性能中甚至更为重要。这项工作有助于进一步理解和优化用于下一代电化学储能材料的非均质复合材料的多孔结构和形态。

著录项

  • 作者

    Hu, Junkai.;

  • 作者单位

    University of Maryland, College Park.;

  • 授予单位 University of Maryland, College Park.;
  • 学科 Analytical chemistry.;Energy.;Inorganic chemistry.;Organic chemistry.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 151 p.
  • 总页数 151
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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