Is Nonflammability of Electrolyte Overrated in the Overall Safety Performance of Lithium Ion Batteries? A Sobering Revelation from a Completely Nonflammable Electrolyte

作者：Hao Jia, Zhijie Yang, Yaobin Xu, Peiyuan Gao, Lirong Zhong, David J. Kautz, Dengguo Wu, Ben Fliegler, Mark Engelhard, Bethany E. Matthews, Benjamin Broekhuis, Xia Cao, Jiang Fan, Chongmin Wang, Feng Lin, Wu Xu · 发表于：Advanced Energy Materials · 年份：2022 · DOI：10.1002/aenm.202203144 · 被引用次数：65 · 研究领域：Advanced Battery Technologies Research、Advanced Battery Materials and Technologies、Advancements in Battery Materials

Abstract It has been widely assumed that the flammability of the liquid electrolyte is one of the most influential factors that determine the safety of lithium‐ion batteries (LIBs). Following this consideration, a completely nonflammable electrolyte is designed and adopted for graphite||LiFePO 4 (Gr||LFP) batteries. Contrary to the conventional understanding, the completely nonflammable electrolyte with phosphorus‐containing solvents exhibits inferior safety performance in commercial Gr||LFP batteries, in comparison to the flammable conventional LiPF 6 ‐organocarbonate electrolyte. Mechanistic studies identify the exothermic reactions between the electrolyte (especially the salt LiFSI) and the charged electrodes as the “culprit” behind this counterintuitive phenomenon. The discovery emphasizes the importance of reducing the electrolyte reactivity when designing safe electrolytes, as well as the necessity of evaluating safety performance of electrolytes on a battery level.