AUTHOR=Merrill Laura C. , Long Daniel M. , Rosenberg Samantha G. , Meyerson Melissa L. , Lam Mila Nhu , Harrison Katharine L. TITLE=Real time lithium metal calendar aging in common battery electrolytes JOURNAL=Frontiers in Batteries and Electrochemistry VOLUME=2 YEAR=2023 URL=https://www.frontiersin.org/journals/batteries-and-electrochemistry/articles/10.3389/fbael.2023.1293877 DOI=10.3389/fbael.2023.1293877 ISSN=2813-4974 ABSTRACT=

Li metal anodes are highly sought after for high energy density applications in both primary commercial batteries and next-generation rechargeable batteries. In this research, Li metal electrodes are aged in coin cells for a year with electrolytes relevant to both types of batteries. The aging response is monitored via electrochemical impedance spectroscopy, and Li electrodes are characterized post-mortem. It was found that the carbonate-based electrolytes exhibit the most severe aging effects, despite the use of LiBF4-based carbonate electrolytes in Li/CFx Li primary batteries. Highly concentrated LiFSI electrolytes exhibit the most minimal aging effects, with only a small impedance increase with time. This is likely due to the concentrated nature of the electrolyte causing fewer solvent molecules available to react with the electrode surface. LiI-based electrolytes also show improved aging behavior both on their own and as an additive, with a similar impedance response with time as the concentrated LiFSI electrolytes. Since I− is in its most reduced state, it likely prevents further reaction and may help protect the Li electrode surface with a primarily organic solid electrolyte interphase.