Revealing the roles of the solid-electrolyte interphase in designing stable, fast- charging, low- temperature Li- ion batteries

• 成果类型: Article
• 署名作者: Tao, Lei; Zhang, Hanrui; Shah, Sameep Rajubhai; Yang, Xixian; Lai, Jianwei; Guo, Yanjun; Russell, Joshua A.; Xia, Dawei; Min, Jungki; Huang, Weibo; Shi, Chenguang; Liang, Zhaohui; Yu, Deyang; Hwang, Sooyeon; Xiong, Hui; Madsen, Louis A.; Zhao, Kejie; Shi, Feifei; Lin, Feng
• 署名单位: Virginia Polytechnic Institute & State University; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Purdue University System; Purdue University; Purdue University in Indianapolis; Boise State University; United States Department of Energy (DOE); Brookhaven National Laboratory; Virginia Polytechnic Institute & State University; Virginia Polytechnic Institute & State University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9219
• DOI: 10.1073/pnas.2420398122
• 发表日期: 2025-04-01
• 关键词: force-field; graphite/electrolyte interface; solvation sheath; transport

摘要

Designing the solid-electrolyte interphase (SEI) is critical for stable, fast-charging, low-temperature Li-ion batteries. Fostering a fluorinated interphase, SEI enriched with LiF, has become a popular design strategy. Although LiF possesses low Li-ion conductivity, many studies have reported favorable battery performance with fluorinated SEIs. Such a contradiction suggests that optimizing SEI must extend beyond chemical composition design to consider spatial distributions of different chemical species. In this work, we demonstrate that the impact of a fluorinated SEI on battery performance should be evaluated on a case-by-case basis. Sufficiently passivating the anode surface without impeding Li-ion transport is key. We reveal that a fluorinated SEI containing excessive and dense LiF severely impedes Li-ion transport. In contrast, a fluorinated SEI with well-dispersed LiF (i.e., small LiF aggregates well mixed with other SEI components) is advantageous, presumably due to the enhanced Li-ion transport across heterointerfaces between LiF and other SEI components. An electrolyte, 1 M LiPF6 in 2-methyl tetrahydrofuran (2MeTHF), yields a fluorinated SEI with dispersed LiF. This electrolyte allows anodes of graphite, mu Si/graphite composite, and pure Si to all deliver a stable Coulombic efficiency of 99.9% and excellent rate capability at low temperatures. Pouch cells containing layered cathodes also demonstrate impressive cycling stability over 1,000 cycles and exceptional rate capability down to -20 degrees C. Through experiments and theoretical modeling, we have identified a balanced SEI-based approach that achieves stable, fast-charging, low-temperature Li-ion batteries.