An Electrochemical Study of the Reactivity at the Lithium Electrolyte/Bare Lithium Metal Interface: I . Purified Electrolytes

Abstract

An in-situ cutting technique was developed to expose bare Li metal in various org. electrolyte environments. Potentiodynamic polarization measurements revealed substantial shifts of the corrosion potential towards pos. values and only a moderate increase of anodic dissoln. for in-situ cut Li metal. Corrosion potential-time transients were measured, commencing at .apprx.50 ms. The following electrolytes were studied: LiAsF6, LiBF4, LiClO4, and Li(CF3SO2)2N (Li bis(trifluoromethanesulfonyl)imide) in THF, 2Me-THF (2-methyltetrahydrofuran), and PC (propylene carbonate). The transients permit the ranking of the reactivity of the electrolytes and show that passivating reactions are often completed in <1 s, even for very carefully purified electrolytes. These measurements shed light on the understanding of the stability of various salts and solvents in contact with Li.