Carbon Nanotube Templated Battery Electrodes

智力优势：提出的研究将开发基于三维碳纳米管复合材料的电化学存储材料。碳纳米管模板微加工（CNT-M）复合材料是由涂有电化学活性材料的垂直排列的碳纳米管模板组成的。这些结构允许在微观和纳米尺度上对材料进行复杂的分层结构。分层结构可以在高容量电池材料中发挥转换作用的应用，如纳米结构硅，这是提出工作的目标。纳米结构硅阳极的研究已经产生了具有极高比容量的材料，但通常还没有产生相应的高面积和体积容量的材料，这也是高容量电池所需要的。此外，由于表面电解质界面（SEI）层的形成，对于这些非常高表面积的材料来说，容量稳定性是一个挑战。我们将制造和测试提供高度结构控制的硅CNT-M阳极，我们将以此为工具研究表面积对SEI稳定性和冲击的影响，以及不同速率下孔径，层厚度和结构对电极容量的影响。我们还将扩展这种制造工艺，为纳米结构硅材料制造微尺度的封装电池，将液体电解质与纳米结构硅表面分离，以控制SEI的稳定性，并大大减少SEI形成的负面影响。简而言之，提出的转换工作将使我们能够以一种以前不可能的方式理解和优化电极结构对储能电极性能的影响。它还有望创造结构工程电极，包括微封装和三维电极，用于新一代高性能电存储设备。拟议工作的目标包括：1。分层结构硅电极的制造。基于模式化VACNT模板的结构可以促进最佳离子和电子导电性，允许使用微封装控制硅/电解质界面，并为三维电池的开发提供平台。CNT-M电极的表征与优化。结构和电化学表征将与计算建模相结合，以确定和量化速率限制机制以及几何形状对速率和稳定性的影响。杨百翰大学已经组建了一支跨学科的专家团队，他们拥有成功的合作记录，以利用这一转型机会。该团队包括一位在纳米制造方面具有专业知识的物理学家，包括在垂直纳米管生长和化学气相沉积方面的广泛工作；另一位在纳米材料表征方面具有专业知识的物理学家，包括透射电子，扫描透射电子，聚焦离子束显微镜和微量分析；在电化学和能量存储材料和系统方面具有专业知识的化学工程师。所提出的工作的智力价值在于它引入了基于模板碳纳米管复合材料的潜在转化电化学材料。这些新材料有潜力开发高能量密度和高功率密度的储能系统，包括3D电极。在我们快速变化的能源生产和输送系统中，迫切需要具有这些特性的能源存储来解决各种各样的问题。这些独特的材料也为限制电极性能的结构因素的基本理解提供了一个控制良好的试验台。更广泛的影响：更广泛的影响包括开发具有重大社会和环境影响潜力的新型储能材料。此外，拟议的工作将涉及在多学科环境中对本科生和研究生的教育，其中具体培训是在储能材料方面。π吗?我们在让本科生参与积极的研究指导环境方面有着悠久的历史，并将继续努力。这项工作的影响将通过一项小学外展方案进一步扩大，该方案将培养和维持代表性不足的群体对科学和技术的兴趣。

Intellectual Merit:The proposed research will develop electrochemical storage materials based on three dimensional carbon nanotube composites. The carbon nanotube templated microfabrication (CNT-M) composites consist of patterned vertically aligned carbon nanotube (VACNT) templates coated with electrochemically active material. These structures allow for complex hierarchical structuring of the material on both the micro and nanoscale. An application where hierarchical structuring could play a transformational role is in high capacity battery materials, like nanostructured silicon, the target of the proposed work. Research on nanostructured silicon anodes has resulted in materials with extremely high specific capacities, but it has not generally resulted in materials with correspondingly high areal and volumetric capacity, which are also required for high capacity cells. Additionally, capacity stability is a challenge on these very high surface areas materials due to the formation of surface electrolyte interphase (SEI) layers. We will fabricate and test silicon CNT-M anodes that will provide a high degree of structural control, which we will use as a tool to study the influence of surface area on SEI stability and impact, and the influence of pore size, layer thicknesses and structure on electrode capacity at different rates. We will also extend this fabrication process to create microscale encapsulation cells for the nanostructured silicon material, separating the liquid electrolyte from the nanostructured silicon surface in order to control SEI stability and dramatically reduce the negative impact of SEI formation. In short, the proposed transformational work will allow us to understand and optimize the influence of electrodestructure on the performance of energy storage electrodes in a way that has not previously been possible.It also holds the promise of creating structurally engineered electrodes, including microencapsulated and three dimensional electrodes, for a new generation of high-performance electrical storage devices.Objectives of the proposed work include:1. Fabrication of hierarchically patterned silicon electrodes. Structures based on patterned VACNT templates that can facilitate optimal ion and electron conductivity, allow for control of the silicon/electrolyte interface using microencapsulation, and provide a platform for the development of three dimensional batteries will be fabricated.2. Characterization and optimization of CNT-M electrodes. Structural and electrochemical characterization will be coupled with computational modeling to identify and quantify rate limiting mechanisms and the influence of geometry on rate and stability.An interdisciplinary team of experts from BYU with an established record of successful collaboration has been assembled to take advantage of this transformational opportunity. The team includes a physicist with expertise in nanofabrication including extensive work in vertical nanotube growth and chemical vapor deposition; another physicist with expertise in nanoscale materials characterization including transmission electron, scanning transmission electron, and focused ion beam microscopy and microanalysis; and a chemical engineer with expertise in electrochemistry and energy storage materials and systems.The intellectual merit of the proposed work is that it introduces potentially transformational electrochemical materials based on templated carbon nanotube composites. These new materials have the potential to enable the development of energy storage systems with both high energy density and high power density, including 3D electrodes. Energy storage with these characteristics is desperately needed to address a wide variety of issues in our rapidly changing energy generation and delivery systems. These unique materials also provide a well-controlled test bed for fundamental understanding of the structuralfactors that limit electrode performance.Broader Impacts:The broader impacts include the development of new energy storage materials with the potential to have significant societal and environmental impact. In addition, the proposed work will involve education of undergraduate and graduate students in a multidisciplinary environment where the specific training is in energy storage materials. The PI?s have a long track record of involving undergraduates in apositive research mentoring environment and will continue this effort. The impact of the work will be extended further through a primary school outreach program that will develop and sustain interest in science and technology by underrepresented groups.