Laboratoire de Réactivité et de Chimie des Solides, UMR CNRS 6007, Université de Picardie Jules Verne, 33 Rue Saint Leu, 80039 Amiens, France.
Anal Chem. 2011 Jan 15;83(2):478-85. doi: 10.1021/ac101948u. Epub 2010 Dec 14.
To allow electric vehicles to be powered by Li-ion batteries, scientists must understand further their aging processes in view to extend their cycle life and safety. For this purpose, we focused on the development of analytical techniques aiming at identifying organic species resulting from the degradation of carbonate-based electrolytes (EC-DMC/LiPF(6)) at low potential. As ESI-HRMS provided insightful information to the mechanism and chronological formation of ethylene oxide oligomers, we implemented "gas" GC/MS experiments to explore the lower mass range corresponding to highly volatile compounds. With the help of chemical simulation tests, we were able to discriminate their formation pathways (thermal and/or electrochemical) and found that most of the degradation compounds originate from the electrochemically driven linear alkyl carbonate reduction upon cycling and to a lesser extent from a two-step EC reduction. Deduced from these results, we propose an overall electrolyte degradation scheme spanning the entire mass range and the chemical or electrochemical type of processes.
为了使锂离子电池能够为电动汽车供电，科学家们必须进一步了解其老化过程，以延长其循环寿命和安全性。为此，我们专注于开发分析技术，旨在识别碳酸盐基电解质（EC-DMC/LiPF(6)）在低电位下降解产生的有机物种。由于 ESI-HRMS 为氧化乙烯低聚物的机制和时间形成提供了有见地的信息，我们实施了“气体”GC/MS 实验，以探索对应于高挥发性化合物的更低质量范围。借助化学模拟测试，我们能够区分它们的形成途径（热和/或电化学），并发现大多数降解化合物源自循环过程中电化学驱动的线性烷基碳酸酯还原，而在较小程度上源自两步 EC 还原。根据这些结果，我们提出了一个涵盖整个质量范围以及化学或电化学类型过程的整体电解质降解方案。
