In-situ characterization of discharge products of lithium-oxygen battery using Flow Electrochemical Atomic Force...

The increasing interest in lithium-oxygen batteries (LOB), having the highest theoretical energy densities among the advanced lithium batteries, has triggered the search for in-situ characterization techniques, including Electrochemical Atomic Force Microscopy (EC-AFM). In this work we addressed the characterization of the formation and decomposition of lithium peroxide (Li₂O₂) on a carbon cathode using a modified AFM technique, called Flow Electrochemical Atomic Force Microscopy (FE-AFM), where an oxygen-saturated solution of the non-aqueous lithium electrolyte is circulated through a liquid AFM cell. This novel technique does not require keeping the AFM equipment inside a glove-box, and it allows performing a number of experiments using the same substrate with different electrolytes without disassembling the cell. We study the morphology of Li₂O₂ on graphite carbon using lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) in dimethyl sulphoxide (DMSO) as electrolyte under different operational conditions, in order to compare our results with those reported using other electrolytes and in-situ and ex-situ EC-AFM.