Determining the Origin of Lithium Inventory Loss in NMC622||Graphite Lithium Ion Cells Using an LiPF6-Based Electrolyte

X-ray photoelectron spectroscopy (XPS) is often used in interphase investigations of lithium ion batteries (LIBs). Yet, it unclear, if its results convey an accurate picture the loss aged LIBs. Herein, electrochemical and surface analytical approaches were to separately quantify contribution growth For this, LIB pouch cells (NMC622||graphite, 5 Ah) for 400 full cycles at 20 °C or 60 °C. Electrodes harvested post mortem subsequent metal battery showed notably higher reversible irreversible after than cycling. While interphases did not increase thickness with aging, area both electrodes increased, leading more electrolyte decomposition larger loss. Along increase, heterogeneous product residues on negative electrode cathode|electrolyte charge-transfer resistances observed. In conclusion, applied combination XPS nitrogen adsorption can homogenously distributed layers thicknesses <10 nm, but thick arising need alternative quantification method highlighted.