Lithium Bis(Trifluoromethanesulfonyl)Imide (LiTFSI): A Prominent Lithium Salt in Lithium-Ion Battery Electrolytes - Fundamentals, Progress, and Future Perspectives

Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is a widely used lithium (Li) salt that is extensively studied in the field of electrolytes for Li-ion batteries (LIBs) to improve their performance. A thorough understanding of its underlying mechanisms in LIBs is crucial for gaining deeper insights into its future development. This paper provides an extensive review of the role of LiTFSI in enhancing battery performance, including its benefits for negative electrode protection, the facilitation of fast charging capabilities, and the promotion of battery operation across a wide temperature range. It also highlights the specific drawbacks of LiTFSI in the electrolyte domain and examines potential solutions. By leveraging the unique properties of LiTFSI, the strategies for its effective utilization in current research are outlined. Finally, the paper discusses the lack of research into the mechanism of LiTFSI in interface protection, particularly the evolution mechanisms of multi-component Li salts at the positive and negative electrode interfaces, and it reasonably anticipates the potential applications of LiTFSI in the realm of non-liquid batteries. This study not only provides a more comprehensive and profound understanding of LiTFSI but also aids in the exploration of novel electrolyte systems. LiTFSI shows high solubility due to its structure, which enhances delocalization of negative charges. It is thermally stable, resists hydrolysis, and has high ion conductivity, making it a promising electrolyte salt for Li-ion batteries. However, its passivation capability toward the positive electrode need improvement, prompting research in using LiTFSI in multi-component Li salt electrolytes for enhanced performance. image