Lifetime Study of High Performance LiNi0.5Mn0.3Co0.2O2/Graphite Pouch Cells Under Fast Charging Conditions Via in Situ Synchrotron X-Ray Diffraction

High performance LiNi0.5Mn0.3Co0.2O2/graphite pouch cell batteries have been studied via high energy X-ray diffraction whole cell mapping over 1200 cycles of extended, fast charge cycling. Position dependent lithium balance quantification in the anode and cathode has been developed via a diffraction-based method and used to visualize and quantify heterogeneity and capacity fade mechanisms. Early, middle, and late stage cycle life are studied in terms of lithium heterogeneity, lithium inventory, and lithium plating as a function of areal position and compared to corresponding electrochemistry.