Characterizing The Morphological and Crystallographic Behavior of Ni-Rich Li-Ion Cathodes

High Ni content cathodes display large volumetric changes and can incur crystallographic phase changes during formation and initial activation. The heterogeneous geometric and crystallographic evolution of the electrodes greatly influence their cycle-life performance. This work will focus on the application of advanced electron and X-ray microscopy techniques to characterize the evolution of heterogeneous particle morphology and crystallographic phases during formation, activation, and throughout the cycle-life of the cathodes. Focused-ion beam electron back scatter diffraction (FIB-EBSD) is applied to characterize the grain size distribution and orientations through the particle architectures. X-ray nano- computed tomography (nano-CT) is applied before and after formation and cycling to quantify morphological change such as crack growth throughout the life of the cathode materials. Finally, synchrotron X-ray diffraction computed tomography (XRD-CT) captures the efficacy of high-voltage activation steps during formation to irreversible form a stable layered phase for high performance long-life cycling. The multi-modal approach provides a comprehensive description of the morphological and crystallographic phenomena that determine the performance of earth-abundant cathodes and sheds new light on performance limiting material properties.