Understanding the Stability and Reactivity of Radical Cations for Improved Overcharge Protection in Lithium-Ion Batteries

肯塔基大学的Susan A. Odom教授将通过这项由化学结构、动力学和机制B项目资助的奖项，寻求提高芳族分子自由基阳离子形式的稳定性，这些芳族分子用作氧化还原穿梭电解质添加剂，用于锂离子电池的过充保护。自由基阳离子在各种溶剂环境中的寿命，包括用作电池电解质的碳酸盐，将被表征以确定氧化后的分解产物。对这些产物的分析将确定(i)溶剂环境如何影响反应结果，（ii）什么特征导致更稳定的自由基阳离子，以及（iii）自由基阳离子持久性与锂离子电池氧化还原穿梭分解前的过充保护循环次数之间是否存在相关性。将合成新的阴极材料的高氧化电位穿梭体，并将探索通过将其置于保护笼中和延长电子离域来稳定所产生的自由基阳离子的方法。这项研究项目的结果有可能为科学界和我们的社会在开发新材料方面提供好处，以提高储能材料的性能和安全性，特别是锂离子电池。随着混合动力汽车的数量和可再生能源存储需求的不断增长，拥有可靠的能源存储变得更加重要。电解质添加剂可以提高锂离子电池的安全性和使用寿命，从而加快该技术在多种应用中的发展。该项目将使不同层次的学生（高中、本科生和研究生）在一个日益重要的社会和实践领域接触科学研究。

Through this award, funded by the Chemical Structure, Dynamics, and Mechanisms - B Program of the Division of Chemistry, Prof. Susan A. Odom from the University of Kentucky will seek to improve the stability of radical cation forms of aromatic molecules used as redox shuttle electrolyte additives for overcharge protection in lithium-ion batteries. The lifetimes of the radical cations in a variety of solvent environments, including carbonates used as battery electrolytes will be characterized to determine decomposition products upon oxidation. Analysis of these products will determine (i) how solvent environment affects the reaction outcome, (ii) what features results in more stable radical cations, and (iii) if there is a correlation in radical cation persistence vs. the number of cycles overcharge protection in a lithium-ion battery before redox shuttle decomposition. Higher oxidation potential shuttles for new cathode materials will be synthesized and methods to stabilize the resulting radical cations, by surrounding them in protective cages and extending electronic delocalization, will be explored.The results of this research project have potential to provide benefits to the scientific community and our society in the development of new materials for the improved performance and safety of energy storage materials, specifically lithium-ion batteries. As the number of hybrid electric vehicles and the need for storage of renewable energy sources continue to grow, it becomes more important to have reliable energy storage. Electrolyte additives that improve the safety and lifetimes of lithium-ion batteries are needed to expedite the growth of this technology for use in multiple applications. This project will expose students at different levels (high school, undergraduate, and graduate students) to scientific research, in a growing area of social and practical importance.