Multi Length Scale Microstructural Investigations of a Commercially Available Li-Ion Battery Electrode

Abstract

Here we present detailed microstructural investigations of a commercially available Li-ion battery cathode. Without a priori knowledge of the cathode material, we have conducted a thorough multi-modal analysis of the battery electrode using XRD, multi-length scale X-ray microscopy (XRM) and electron microscopy. Multiple length scale X-ray microscopy experiments reveal a wealth of microstructural information in three dimensions including phase fractions, volume specific surface area and tortuosity. At the highest resolution, XRM also reveals internal defects in the solid structure. The resolution requirement for three-dimensional microstructural characterization is found to be specific to the physical parameter under investigation, demonstrating the need for a multi-length scale approach. This is especially true for surface area which increases with increasing resolution in a fractal-like way.