Probing the Effect of Ion Insertion on the Mechanical Stability of High Capacity Nanocomposite Anodes

硅基电极由于其高能量存储密度而成为锂离子电池最有前途的下一代阳极，但由于其由于机械断裂而很快失效，因此尚未商业化。钠离子电池锡阳极的商业化必须克服由机械不稳定性引起的类似快速失效。具有最有希望的微观结构的材料，可以限制这种断裂或不稳定是涂有基体的硅或锡纳米颗粒。该奖项将采用综合实验-计算方法来研究这些纳米复合材料的机械行为，并预测锡或硅颗粒的尺寸、基体材料和电池性能之间的相互作用。该研究的成功结束将促进跨学科科学的进步，并在应用方面为下一代电极的商业化提供设计指导。由此产生的锂离子电池将比目前的电池具有更长的使用寿命和更小的尺寸，并且将有广泛的应用，从手机到电动汽车。钠离子电池比锂离子电池的体积更大，因此将与可再生能源结合使用。因此，这个项目也将使美国经济更加可持续和环保，从而促进国家的健康、繁荣和福利。研究结果将分发给高中和科学博物馆，以激励年轻学生，特别是少数民族学生学习科学和工程。为了充分了解纳米复合阳极的力学行为，将采用跨学科的方法，将详细的电化学实验与多物理场建模相结合。具体的重点是确定锂离子（或钠离子）插入和去插入对聚合物涂层的硅和/或锡纳米颗粒的影响。将制定并实施一个新的计算模型，该模型将允许预测颗粒尺寸和聚合物涂层的适当组合，从而抑制电池运行过程中纳米复合阳极界面的损伤。在理论预测的基础上，将制作和测试新的阳极。特别是高分辨率的电子显微镜将能够捕捉到颗粒-聚合物界面的损伤程度并验证模型。实验验证后，设计指南将提供给电池开发人员制造下一代锂离子电池和钠离子电池电极。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。

Silicon based electrodes are the most promising next generation anodes for Li-ion batteries due to their high energy storage density, however, they have not been commercialized because they fail due to mechanical fracture very quickly. A similar rapid failure due to mechanical instability must be overcome in commercializing tin anodes for sodium-ion batteries. The material with the most promising microstructure that can limit such fracture or instability is that of silicon or tin nanoparticles coated with a matrix. The present award will use an integrated experimental-computational approach to investigate the mechanical behavior of these nanocomposites and will predict the interplay between the size of the tin or silicon particles, the matrix material, and battery performance. The successful end to the research will promote the progress of interdisciplinary science and, on the application side, provide design guidance for commercializing next generation electrodes. The resulting lithium-ion batteries will have a longer lifetime and smaller dimensions than the current ones, and will have a wide range of applications from cell phones to electric vehicles. Sodium-ion batteries occupy larger volumes than lithium-ion and therefore will be used in combination with renewable energy sources. This project will, therefore, also allow for a more sustainable and environmentally friendly US economy, thus advancing the national health, prosperity, and welfare. The results will be disseminated to high schools and science museums to motivate young students, especially from minorities, to study science and engineering.To fully understand the mechanical behavior of nanocomposite anodes an interdisciplinary approach will be followed which combines detailed electrochemical experiments along with multiphysics modeling. The specific focus is to determine the effect of lithium-ion (or sodium-ion) insertion and de-insertion on silicon and/or tin nanoparticles coated with polymers. A new computational model will be formulated and implemented, which will allow for the prediction of the appropriate combination of particle size and polymer coating that will inhibit damage at the interfaces of the nanocomposite anodes during battery operation. Based on the theoretical predictions new anodes will be fabricated and tested. Particularly high-resolution electron microscopy will be able to capture the extent of damage at the particle-polymer interface and verify the model. After experimental validation, design guidance will be available for battery developers to fabricate next generation electrodes for both lithium and sodium ion batteries.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.