Annealing‐Induced Dynamic Strain Evolution in Cycled High‐Ni Layered Oxides Revealing Latent Lattice Imperfections

Abstract High‐Ni layered oxides undergo distinct chemomechanical evolution upon high‐voltage charging over 4.2 V, producing crystallographic defects and associated lattice distortions within the cathode particles. Due to the significant recovery of chemomechanical evolutions during discharging, lattice imperfections resulting from high‐voltage charging tend to remain hidden and pose challenges in their characterization at discharged states. Moreover, their impact on the structural stability and electrochemical performance of cathode materials remains elusive. In this study, synchrotron‐based X‐ray diffraction and Bragg coherent diffraction imaging (CDI) successfully detects subtle yet persistent lattice distortions in the discharged state after high‐voltage cycling. In situ Bragg CDI further reveals internal strain evolution within the particles upon mild heating, which can be correlated…