Investigations on LiF as Protective Layer for Lithium Metal Electrodes

Abstract

The improvement of lithium-ion batteries is necessary to get a higher specific capacity which is especially needed for the electromobility to ensure higher driving ranges. State of the art batteries offer specific energy densities of about 200 Wh/kg, which can be raised up to 350 Wh/kg with lithium metal as anode material. There are a few challenges upcoming with the usage of lithium metal due to its high reactivity. One approach to increase the chemical and electrochemical stability of lithium metal is a proper coating, for which lithium fluoride is a promising candidate due to its chemical stability and high surface energy.Different reported coating methods were used to obtain LiF coatings with different morphologies and thicknesses e.g., immersion in a NH4HF2/DMSO solution or gas phase reaction with R-134a. To investigate the influence of LiF on lithium metal, different analytical methods were carried out, focusing on the chemical stability at ambient conditions and electrochemical performance during plating/stripping cycles. The aim of this project is to re-evaluate the impact of LiF coatings on the stability of lithium metal electrodes.