Evidencing depth-resolved Li heterogeneties and Li plating across graphite electrodes during fast charging with microXRD

We propose to use operando micro X-ray diffraction (μXRD) to follow the depth-resolved lithiation state of graphite electrodes and possible lithium plating occurring during fast charging. Since heterogeneous lithiation and Li plating result in premature electrode ageing, there is a crucial need to experimentally probe these phenomena and to numerically predict their occurrence and magnitude. We have addressed the latter by developing a physics-based Newman-type performance model [2], the accuracy of which has been experimentally verified at the macro and micro scale for moderate C-rate using the feedback from our previous synchrotron experiment on ID13 (MA4110). To go further, we now require new experimental data (i) to adjust the performance model for the fast charge regimes, and (ii) to quantify lithium plating through the electrode thickness as function of the local state of graphite lithiation. This will provide a sound basis for accurate prediction of electrode ageing.