Electron spectroscopic and electrochemical investigations of surface reactions of lithium.

Abstract

The growing technological application of metallic lithium has produced a greater need to understand its fundamental surface chemical properties. The use of lithium as an anode in high-energy density battery systems represents one application where this knowledge is required to optimize system performance. The surface chemistry of lithium will be discussed in terms of oxidants which represent the reductive half-cell components of these batteries, contaminants present during cell fabrication, and solvents used as the electrolytic medium. These systems have been studied in the low pressure limit ( < 1 millitorr) at atomically clean lithium surfaces using X-ray Photoelectron Spectroscopy (XPS). The lithium/sulfur dioxide system has been singled out for detailed study in order to explore the relationship between gas-phase and solution-phase processes. Electrochemical characterization of the lithium anode has been conducted as a function of controlled surface composition within this system. The ability of lithium to induce corrosion at structural components of these batteries (i.e., glass insulators) has also been investigated. A description of the chemical activity of lithium and its consequence has been developed from these results.