AN ELECTROCHEMICAL STUDY OF THE REACTIVITY AT THE LITHIUM ELECTROLYTE BARE LITHIUM METAL INTERFACE .2. UNPURIFIED SOLVENTS

The in situ cutting method to expose bare lithium metal, the corrosion potential-time transients, and voltammetric measurements have been employed to study the behavior of lithium in various organic electrolyte environments. In situ optical and ex situ scanning electron microscopy techniques were used to examine the morphology of Li electrode surfaces, during exposure at open circuit and after anodic polarization. The following electrolytes have been investigated: LiAsF6, LiPF6, LiBF4, LiClO4, and Li(CF3SO2)2N in unpurified THF and PC. Small amounts of water shift the corrosion potential towards more positive values (compared to purified electrolytes). During intensive anodic cycling with LiAsF6/THF the presence of water leads to the breakdown of a surface film and exposure to bare lithium metal.