Optimizing Cycling Stability and Coulombic Efficiency of Nanostructured Si-Based Anode

优化纳米结构硅基阳极的循环稳定性和库伦效率

• 批准号: 1206462
• 负责人: Se-Hee Lee
• 金额: $ 40.85万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206462&HistoricalAwards=false
• 关键词: Optimizing; Cycling; Stability; Coulombic; Efficiency

NON-TECHNICAL DESCRIPTION: Traditional Li-ion batteries employ carbonaceous anodes, but projected performance targets for next-generation Li-ion batteries require new, higher capacity materials that can be electrochemically cycled in a stable manner. The most attractive candidate to replace carbon is silicon; it has the highest known capacity, is relatively low-cost, and is physically abundant. At present, the drawback with silicon is that a volume expansion on the order of ca. 300% occurs upon Li insertion that leads to rapid capacity fade during cycling. Creative approaches to realize highly-reliable electrodes are being pursued with nanometer-scale materials and geometric architectures; impressive results have been obtained, but a fundamental understanding is still lacking. To this end, this project focuses on understanding the complex phenomena of Li insertion and extraction from Si, and developing novel nanostructured Si-based anodes which can address these critical technical issues with Si anodes.TECHNICAL DETAILS: This project aims to uncover the underlying principles that govern the complex phenomena of Li insertion and extraction from Si, especially the complex interplay among electrochemical surface reactions, transport, mechanical response, and material evolution based on a tightly-coupled experimental-theoretical research. A combination of theoretical electrochemomechanics, hybrid organic-inorganic sol-gel synthesis, in situ monitoring of microstructural developments with a focused ion beam system, and AC impedance measurements allows a systematic exploration of materials chemistries for the creation of nanostructured Si-based anodes. By targeting enhanced cycling stability, mechanical stability, and coulombic efficiency, these core-shell nanostructures are designed to exhibit unsurpassed performance as Li-ion battery anodes. By coupling research discoveries with ongoing and new educational activities, students at all levels (K-12 through graduate) will be exposed to the excitement of renewable energy including energy storage material systems for electric vehicles. Interdisciplinary, tightly integrated research provides a unique environment for the education of a new cadre of scientists and engineers who will become experts in their disciplinary fields and also understand the broader context of sustainable energy; thus, they will be equipped to lead the design of a new sustainable energy future.

非技术描述：传统的锂离子电池使用碳质阳极，但下一代锂离子电池的预期性能目标需要能够以稳定的方式进行电化学循环的新的、更高容量的材料。最有吸引力的替代碳的候选者是硅；它具有已知的最高容量，相对低的成本，并且物理上丰富。目前，硅的缺点是在锂插入时发生约300%的体积膨胀，导致在循环过程中容量迅速衰减。人们正在用纳米材料和几何结构来寻求实现高度可靠电极的创造性方法；已经取得了令人印象深刻的结果，但仍然缺乏基本的理解。为此，本项目致力于了解硅中锂的插入和提取的复杂现象，并开发新型的纳米结构硅基阳极来解决这些关键的技术问题。技术细节：本项目旨在揭示控制硅中锂的插入和提取复杂现象的基本原理，特别是在紧密耦合的实验-理论研究的基础上，揭示电化学表面反应、输运、机械响应和材料演化之间的复杂相互作用。理论电化学力学、有机-无机混合溶胶-凝胶合成、聚焦离子束系统对微结构发展的现场监测以及交流阻抗测量相结合，使人们能够系统地探索材料化学，以创建纳米结构的硅基阳极。通过提高循环稳定性、机械稳定性和库仑效率，这些核壳纳米结构被设计为表现出作为锂离子电池阳极的无与伦比的性能。通过将研究发现与正在进行的和新的教育活动相结合，各级(从K-12到研究生)的学生将接触到可再生能源的兴奋，包括电动汽车的储能材料系统。跨学科、紧密结合的研究为培养新的科学家和工程师队伍提供了独特的环境，他们将成为各自学科领域的专家，并了解可持续能源的更广泛背景；因此，他们将有能力领导设计一个新的可持续能源未来。