Collaborative Research: Manufacturing Mechanically Compliant Silicon Nanostructures for Rechargeable Lithium Ion Batteries

本研究项目旨在研究和论证一种新的制造硅(Si)负极锂(Li)离子电池的概念，即利用弹性衬底上的硅纳米结构作为阳极来释放充放电循环过程中锂离子扩散产生的应力。硅阳极前景看好，正被密切研究用于锂离子电池，因为它们具有已知的最高理论充电容量。然而，由于硅负极锂离子电池在使用过程中，特别是在锂离子的插入和提取过程中，其体积变化很大(4X)，导致粉化和早期容量衰减，严重限制了其使用寿命，因此发展相对滞后。该合作项目的目标是通过对弹性衬底上锂离子插入和拔出过程中硅纳米结构的机械-电化学耦合的新概念的基础研究，解决应力问题并制造硅负极锂离子电池。具体研究将集中在(1)使用弹性基板释放扩散诱导应力的理论理解；(2)在弹性基板上制造各种硅纳米结构作为锂离子电池的阳极；(3)以弹性基板上的纳米结构硅作为负极的锂离子电池的电化学表征；以及(4)开发经济有效的方法和实现可制造性。如果成功，这项合作研究的结果将有助于从根本上理解弹性衬底上硅纳米结构的机械-电化学耦合性质，并为实现硅负极锂离子电池的理论最大能量密度提供有力的手段。将在两个研究机构(特拉华大学和亚利桑那州立大学)建立综合、互动和协作的研究和教育方案。参与拟议研究的研究生和本科生将通过多学科和多大学环境接受培训。研究成果将用于发展和加强本科生和研究生课程。通过与亚利桑那州科学中心的合作，将建立一个面向普通公众的创新外展活动。

This research project aims at investigating and demonstrating a new concept of manufacturing silicon (Si) anode lithium (Li) ion batteries by utilizing Si nanostructures on elastomeric substrates as anodes to release the stress induced by Li ion diffusion during charge-discharge cycles. Si anodes hold great promise and are being closely investigated for use in Li-ion batteries because they have the highest-known theoretical charge capacity. However, the development of Si-anode Li-ion batteries has lagged behind because of their large physical volume change (4X) during use, specifically during the insertion and extraction of Li ions, which results in pulverization and early capacity fading thus severely limiting their useful life. The objective of this collaborative project is to resolve the stress issue and manufacture Si-anode Li-ion batteries through a fundamental investigation of a novel concept of mechanical-electrochemical coupling of Si nanostructures on elastomeric substrates during insertion and de-insertion of Li ions. Specific studies will focus on (1) a theoretical understanding of releasing diffusion-induced stress using elastomeric substrates; (2) manufacturing of various Si nanostructures on elastomeric substrates as anodes in Li-ion batteries, (3) electrochemical characterization of Li-ion batteries with the nanostructured Si on elastomeric substrates as anode; and (4) development of a cost-effective approach and the realization of manufacturability. If successful, the results of this collaborative research will facilitate the fundamental understanding in the coupled mechanical-electrochemical properties of Si nanostructures on elastomeric substrates and provide a powerful means to realize theoretically maximum energy density of Si-anode Li-ion batteries. Integrated, interactive and collaborative research and educational programs in two research institutions (University of Delaware and Arizona State University) will be established. The graduate and undergraduate students involved in the proposed research will be trained through a multidisciplinary and multi-university environment. The research achievement will be used to develop and enhance both undergraduate and graduate courses. An innovative outreach activity toward the general public will be established through the collaboration with the Arizona Science Center.