Collaborative Research: Sodiation Driven Multiscale Chemical-Structural Interactions in Alloy Electrodes

目前迫切需要大幅增加可再生能源在电网中的整合。这些可再生资源固有的间歇性和分散性预示着成本效益的大规模能源储存的发展。这种存储能力为电网的恢复能力提供了额外的好处，这是减轻自然灾害和其他灾难性事件影响所必需的。基于地球资源丰富且成本低廉的材料的电化学储能技术日益受到重视。钠离子电池和锡基合金负极材料是这一需要大容量储能的应用的有前途的技术。通过这一基础研究项目，钠在锡基合金中的储存与钠离子电池性能之间的化学和结构变化之间建立了更强的联系。该研究项目有助于在多学科研究环境中对研究生和本科生进行教育和培训。综合教育和推广计划将为研究生、本科生和高中生创造参与这项研究的机会，并强调增加来自代表性不足群体的学生的参与。研究成果将通过讲座和实验课整合到本科和研究生的课程中。从综合实验、表征和模拟工作中产生的开源数据库将导致能源存储科学的进步。通过促进钠离子电池的未来发展，该项目将有助于满足社会对具有成本效益的电网储能的需求。本研究的主要目的是建立一个全面的知识库，并了解用于钠离子电池的高容量锡（Sn）基合金电极的化学和结构转变。这项工作是基于这样一个假设，即由钠化引起的中尺度形态和化学成分的变化对这种合金电极的不可逆能力有重要影响。实验项目包括电化学测试，电极晶体结构的x射线衍射表征，以及在操作中x射线断层扫描，将与钠离子电池电极微观结构的中尺度计算研究相结合。该综合研究方法将通过实现以下研究目标来验证上述假设：(1)将锡基合金电极晶体结构的变化与电化学性能联系起来；(2)将多尺度合金电极形貌与结构和化学变化联系起来；(3)阐明电极微观结构对输运-电化学相互作用和性能的影响。这项研究将深入了解钠离子电池的微观结构、化学和性能之间的相互作用。结合实验和计算的方法将提供前所未有的细节，合金电极的化学和结构的演变，由于钠化。所获得的见解将有助于未来钠离子电池电极的工程设计，并将产生适用于与其他电池化学相关的一系列电极材料的方法。提议的x射线成像和中尺度建模工作将产生一组记录的3D微观结构数据，这些数据将通过一个开源平台传播，并将支持未来的研究和开发。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

There is a critical need to dramatically increase the integration of renewable energy in the electric grid. The inherently intermittent and diffuse nature of these renewable resources predicates the development of cost-effective, large-scale energy storage. Such storage capabilities offer the added benefit of contributing resilience to the electric grid, which is needed to mitigate the effects of natural disasters and other catastrophic events. Electrochemical energy storage technologies based on earth abundant and cost-effective materials are increasingly needed. The sodium ion battery and tin (Sn) based alloy anode materials are promising technologies for this application that needs high-capacity energy storage. Through this fundamental research project, stronger connection is made between the chemical and structural changes due to sodium storage in Sn-based alloys and the resulting performance of the sodium ion battery. The research project contributes to the education and training of both graduate and undergraduate students within a multidisciplinary research environment. The integrated education and outreach plan will create opportunities for graduate, undergraduate, and high school students to be involved in this research and places a strong emphasis on increasing the participation of students from underrepresented groups. Research findings will be integrated into the curriculum at the undergraduate and graduate level through lectures and laboratory classes. A library of open-source data generated from the comprehensive experiment, characterization, and simulation efforts will lead to the advancement of energy storage science. By facilitating the future development of sodium ion batteries, the project will help contribute to the societal need for cost-effective grid energy storage. The principal objective of this research is to develop a comprehensive knowledge base and understanding of the chemical and structural transformations in high-capacity tin (Sn) based alloy electrodes for sodium ion batteries. This work is predicated on the hypothesis that changes in mesoscale morphology and chemical composition caused by sodiation contribute significantly to the irreversible capacity of such alloy electrodes. An experimental program including electrochemical testing, X-ray diffraction characterization of electrode crystal structure, and in operando X-ray tomography will be coupled with mesoscale computational studies of sodium ion battery electrode microstructures. This comprehensive research approach will test the above hypothesis by achieving these research objectives: (1) correlate changes in Sn-based alloy electrode crystal structure with electrochemical performance; (2) correlate multiscale alloy electrode morphology with structural and chemical changes; and (3) clarify the influence of electrode microstructure on the transport-electrochemistry interaction and performance. The research will provide insight into the interactions between microstructure, chemistry, and performance in sodium ion batteries. The combined experimental and computational approach will provide unprecedented details on the chemical and structural evolution of alloy electrodes due to sodiation. The insights gained will facilitate engineering of future sodium ion battery electrodes and will yield methods applicable to an array of electrode materials relevant to other battery chemistries. The proposed X-ray imaging and mesoscale modeling efforts will yield a documented set of 3D microstructural data, which will be disseminated through an open-source platform and will support future research and development.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.