Performance Improvement of Lithium Metal Batteries Enabled By LiBF3CN as a New Electrolyte Additive. Issue 11 (1st November 2022)

• Record Type: Journal Article
• Authors: Chae, Oh B.; Adiraju, Venkata A. K.; Lucht, Brett L.
• Is Part Of: Journal of the Electrochemical Society. Volume 169:Issue 11(2022)
• Publication Date: 2022-11-01
• Subjects: Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/1945-7111/ac9d67
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : A newly synthesized electrolyte additive, lithium trifluoro(cyano) borate (LiBF3 CN), has been investigated for electrochemical performance improvement of lithium metal batteries. The LiBF3 CN has a structure where one fluorine atom of BF4 − is substituted with a cyano group (−CN) prepared by the reaction of boron trifluoride etherate with lithium cyanide. The electrochemical performance in symmetric Li/Li cells and NCM523/Li cells is significantly improved upon the incorporation of LiBF3 CN as an electrolyte additive into a carbonate-based electrolyte. Extensive characterization of the deposited lithium metal reveals that a thin (≈20 nm) and robust SEI composed of LiNx Oy, Li3 N and Li2 O is formed by the reductive decomposition of the LiBF3 CN additive, which plays an important role in decreasing the resistance and stabilizing lithium deposition/stripping. The insight into the substitution effect of a functional group obtained from this work provides guidance for the design of new electrolyte additives.