CAREER: In Situ Observation of Coupled Transport and Degradation in Battery Electrodes

交通运输占美国能源消耗的25%到30%。电动汽车是减少交通运输化石燃料消耗的一种替代方案。电动汽车需要可充电电池，以平衡电能存储和电力输送需求，这些电池必须具有支持可承受的拥有成本的使用寿命。锂离子电池是目前电动汽车应用的领先技术。锂离子电池的功率和能量存储能力可以通过利用纳米技术原理在纳米尺度上构建的电池电极材料来增强。然而，纳米结构电极的使用可能会加速电极退化，从而缩短电池寿命。该研究奖项旨在了解纳米结构锂离子电池电极在现实条件下充放电过程中的退化。这将通过使用先进的x射线成像技术来可视化电池电极在操作过程中发生的情况来实现，这是以前从未做过的。从拟议的研究中获得的见解将导致提高电池性能和可靠性的电池材料结构。这些改进反过来又有可能延长混合动力和电动汽车的行驶里程和使用寿命。与该奖项相关的教育和推广计划将为机械工程本科学生提供能源存储过程的实践经验。CAREER奖的技术目标是通过电池充放电过程中的原位三维（3-D） x射线成像技术，对导致锂离子电池纳米尖晶石阴极退化的过程有一个基本的了解。该研究将验证高功率锂离子电池的纳米结构阴极在高温下由于阴极活性材料的金属溶解增强而加速降解的假设。这一假设将通过制造具有有序和不规则微观结构的电极，表征电极在一定温度范围内的性能，并使用x射线纳米断层扫描直接观察三维微观结构来验证。在这一研究计划的过程中，期望在电化学能量转换和存储领域做出新的贡献。这些贡献包括使用3-D x射线材料断层成像来帮助阐明电极微观结构和降解机制之间的相互作用，揭示纳米结构电池结构的优点和挑战，以及通过电化学测试生成一组与电池性能和降解相关的锂离子电池材料的3-D微观结构数据。与该职业奖相关的教育和推广计划将为机械工程本科学生提供储能过程的实践经验。为本科实验室开发的储能实验将适应为学校的K-12教师培训项目提供模块，这些学校为STEM领域代表性不足的群体提供服务，还将支持在阿拉巴马州亨茨维尔的美国太空和火箭中心举办展览，吸引不同的观众参与储能主题和概念。

PI Name: Nelson Proposal ID: 1454437 Transportation accounts for 25% to 30% of U.S. energy consumption. Electric vehicles are one alternative to reducing fossil fuel consumption for transportation. Electric vehicles require rechargeable batteries that balance the electrical energy storage and power delivery needs, and these batteries must have lifetimes that support affordable cost of ownership. The lithium-ion battery is currently the leading technology for electric vehicle applications. Lithium-ion battery power and energy storage capacity can be enhanced by utilizing battery electrode materials that are structured at the nanoscale using principles of nanotechnology. However, the use of nanostructured electrodes may accelerate electrode degradation that reduces battery life. This research award seeks to understand degradation in nanostructured lithium-ion battery electrodes during charging and discharging under realistic conditions. This will be accomplished by using advanced x-ray imaging techniques to visualize what happens to the battery electrode during operation, which has never been done before. Insights from the proposed research will lead to battery material structures that improve battery performance and reliability. These improvements in turn have potential to extend the range and lifetime of hybrid and electric vehicles. The education and outreach programs associated with this award will provide mechanical engineering undergraduate students with hands-on experiences in energy storage processes. The technical goal of this CAREER award is develop a fundamental understanding of the processes leading to degradation of nanostructured spinel cathodes for Li-ion batteries through in situ three-dimensional (3-D) X-ray imaging techniques during battery charge and discharge. The proposed research will test the hypothesis that nanostructured cathodes for high power lithium-ion batteries exhibit accelerated degradation at elevated temperature due to enhanced metal dissolution from the cathode active material. This hypothesis will be tested by fabricating electrodes with ordered and irregular microstructure, characterizing electrode performance over a range of temperatures, and directly observing 3-D microstructure using X-ray nanotomography. During the course of this research program, new contributions to the fields of electrochemical energy conversion and storage are expected. These contributions include the use of 3-D X-ray material tomatographic imaging to help elucidate the interactions between electrode microstructure and degradation mechanisms, revealing the merits and challenges of nanostructured battery architectures, and generation of a documented set of 3-D microstructural data for lithium-ion battery materials that is correlated to battery performance and degradation through electrochemical testing. The education and outreach programs associated with this CAREER award will provide mechanical engineering undergraduate students with hands-on experiences in energy storage processes. Energy storage experiments developed for undergraduate laboratories will be adapted to provide modules for K-12 teacher training programs in schools that serve under-represented groups in STEM fields, and will also support development of exhibits at the U.S. Space and Rocket Center in Huntsville, Alabama that engage diverse audiences with energy storage topics and concepts.