An atomistic molecular dynamics study of O₂ diffusion in Metal-Air batteries

In recent years significant effort has been devoted to vehicle electrification. Rechargeable systems, and in particular Li-air batteries were recognized as appealing candidates for this application . Choosing an appropriate electrolyte, whose properties optimize the electro-chemical cell, is a central aspect of the battery design .

The ethers based electrolytes are commonly used due to their low cost and promising stability. However ethers easily wet the air channels within the carbon cathode and thus the oxygen must transport through the ether medium. The solubility and diffusivity of O₂ in this medium are poor and effectively limit the kinetics of the reaction . One of the possible solutions is to introduce a perfluorocarbons (PFC) phase to the cathode surface . This phase provides a better O₂ transport medium and competes with the flooding of the cathode porous by the ethers.

In this work we present a study of glycol ethers - PFC combined liquid, based on atomistic molecular dynamics techniques. We explore a variety of experimentally available materials for possible solvents and provide computation insights to its miscibility and diffusion rates.