Electron Backscatter Diffraction for Investigating Lithium-Ion Electrode Particle Architectures

The performance and degradation of layered cathode materials for lithium-ion batteries depend on their morphological, surface, and crystallographic properties. A comprehensive tool to spatially characterize grain geometry and orientation in electrode particles is needed in order to understand solid-state lithium transport and the efficacy of particles to avoid lithiation heterogeneities and strain-induced degradation. Here we apply electron backscatter diffraction on LiNi0.5Mn0.3Co0.2O2 particle cross-sections to spatially describe intra-particle grain architectures. A method for segmenting, labeling, and quantifying morphological properties of distinct grains is developed and applied. Crystallographic orientations are measured for each grain, and the spatial distribution of grain orientations is quantified with a specific focus on describing lithium transport and accounting for inter-grain lithiation barriers. The necessary extension from two-dimensional to three-dimensional descriptions of grain morphologies and orientations to predict lithiation inefficiencies is discussed, as well as a method to quantify the ideality of grain architectures for high-rate and efficient operation.