GOALI: Stress Evolution and Related Phenomena in Composite Electrodes for Li Ion Batteries

这项研究的中心目标是促进对锂插入电池电极材料的理解，关于机械限制（即，应力和应变）。 候选电极材料的体积膨胀非常大，并且它们的基本变形性质没有很好地表征。 由于这些原因，我们将开始与薄膜配置的详细研究，与测量的平面应力（基于晶片曲率），平面外的膨胀和横向不均匀性（基于干涉），和变形性能（基于纳米压痕）。 通过在Li插入和移除过程中原位进行这些实验，我们将能够详细了解目前无法获得的材料行为。 这些实验将与几个不同长度尺度的模型开发密切结合。 连续体建模是必要的实验分析，并最终开发改进的电池电极的设计方法。 原子模型将提供对基本材料和相关界面的基本性质的详细了解。在这些努力中使用的集成方法将适用于广泛的电池电极，但在本计划中，我们将特别关注负极中的碳和硅材料。改善锂离子电池性能是混合动力和电动汽车近期发展的关键需求。 计划中的研究，无论是方法还是实际结果，都旨在通过提供有关材料性能的重要基础信息，为新电池技术做出重大贡献。 通用汽车公司科学家的直接参与为传播这一知识提供了重要途径。 获得所需资金支持的研究生和博士后助理将通过各种方法开发跨学科专业知识。 与工业参与者直接合作将为他们的教育提供一个重要的补充层面，这两个人将在电池相关领域的未来工作中处于有利地位。我们还计划让至少六名本科研究人员和一名或多名高中生参与这项工作的不同方面。

The central goal of this research is to advance the understanding of Li insertion in battery electrode materials, with respect to mechanical limitations (i.e., stress and strain). The volume expansion of the candidate electrode materials are very large, and their basic deformation properties are not well characterized. For these reasons, we will begin with detailed studies of thin film configurations, with measurements of in-plane stresses (based on wafer curvature), out-of-plane expansions and lateral inhomogeneities (based on interferometry), and deformation properties (based on nano-indentation). By performing these experiments in situ during Li insertion and removal, we will be able to obtain detailed understanding of the materials behavior which are not currently available. These experiments will be closely coupled with model development at several different length scales. Continuum modeling is necessary for analysis of the experiments, and ultimately for developing improved design methodologies for battery electrodes. Atomistic modeling will provide detailed insight into the fundamental properties of the basic materials and the relevant interfaces. The integrated approach used in these efforts will be applicable to a wide range of battery electrodes, but in this program we will specifically focus on carbon and silicon materials in negative electrodes.Improved Li ion battery performance is a critical need for the near-term development of hybrid and electric vehicles. The planned research, both the methodology and the actual results, are designed to make significant contributions to new battery technology by providing important fundamental information about materials performance. The direct involvement of General Motors scientists provides an important avenue for disseminating this knowledge. The graduate student and post-doctoral associate who are supported with the requested funds will develop interdisciplinary expertise with a variety of methods. Working directly with the industrial participants will provide an important added dimension to their education, and both of these individuals will be well positioned for future work in battery-related fields. We also plan to involve at least six undergraduate researchers and one or more high school students with different aspects of this work.