The Application of Electron Backscatter Diffraction for Investigating Intra-Particle Grain Architectures and Boundaries in Lithium Ion Electrodes

Abstract

The performance and degradation of layered cathode materials for lithium-ion batteries are largely governed by their morphological and crystallographic properties. A comprehensive tool to spatially characterize grain architectures in electrode particles is needed 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, labelling, 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 the plane along which lithium transports, accounting for inter-grain lithiation barriers and for favorable inward lithiation of the particle. The extension from 2D to 3D 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.