Lithium electrodes with and without CO₂ treatment: Electrochemical behavior and effect on high rate lithium battery performance

The ionic resistivity and integrity of a solid-electrolyte interphase (SEI) film on a lithium electrode surface was investigated. The preformed lithium carbonate film on the surface of the lithium electrode was found to improve the electrode behavior by maintaining a low ionic resistance. In lithium/silver vanadium oxide batteries, voltage delay can be eliminated with the use of a lithium anode pretreated with CO₂. An SEI consisting of lithium carbonate appears to be responsible. Unlike the surface film formed from lithium-electrolyte reactions, the lithium carbonate film is relatively strong and can withstand high current density pulses (∼20 mA/cm²) without significant damage. An ion exchange mechanism involving the carbonate anion is proposed.