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

本研究项目旨在研究和展示一种制造硅（Si）阳极锂（Li）离子电池的新概念，该电池利用弹性衬底上的硅纳米结构作为阳极，以释放充放电循环中锂离子扩散引起的应力。由于硅阳极具有已知的最高理论充电容量，因此它在锂离子电池中的应用正受到密切的研究。然而，由于硅阳极锂离子电池在使用过程中，特别是在Li离子的插入和提取过程中，其物理体积变化大（4X），导致粉末状和早期容量衰退，严重限制了其使用寿命，因此其发展滞后。该合作项目的目标是通过对弹性衬底上硅纳米结构在插入和脱插入过程中机械-电化学耦合的新概念的基础研究，解决应力问题并制造硅阳极锂离子电池。具体的研究将集中在(1)利用弹性体衬底释放扩散诱导应力的理论理解；(2)弹性体衬底上各种硅纳米结构作为锂离子电池阳极的制备；(3)弹性体衬底上纳米结构硅作为阳极的锂离子电池电化学表征；(4)开发具有成本效益的方法并实现可制造性。如果成功，该研究结果将促进对弹性衬底上硅纳米结构耦合力学-电化学特性的基本理解，并为实现硅负极锂离子电池理论上最大能量密度提供有力手段。两所研究机构（特拉华大学和亚利桑那州立大学）将建立综合、互动和合作的研究和教育项目。参与拟议研究的研究生和本科生将通过多学科和多大学的环境进行培训。研究成果将用于发展和加强本科和研究生课程。通过与亚利桑那科学中心的合作，将建立一个面向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.