Using X-Ray Diffraction to Map the Electrochemical Spatial Inhomogeneity within Li-Ion Batteries
The Li1+xTM1-xO2compounds are leading candidates for the next generation of lithium batteries. Due to constraints imposed by the complex electrode morphology, the mechanical stresses often lead to cracking within, and at the boundaries between, oxide particles. We have conducted a systematic experimental study to determine the evolution in these oxide materials as a function of electrode cycling, position in the battery cell, and aging conditions.
High-energy x-rays are able to penetrate through large amounts of material so that the diffraction signal probes the entire depth of the battery cells, including multiple layers of aluminum and copper current collectors and transition-metal laden electrodes. The diffraction signal provides information on the lattice parameters for the active materials, which changes as the battery cell is cycled. Results for a study of the spatial inhomogeneity that is present in a NMC523(+)/Graphite(-) battery with a prismatic form factor will be discussed.