Unveiling the degradation mechanisms and addressing sensitivity challenges in nickel-rich cathodes via advanced characterization

Abstract

Nickel-rich layered oxide cathodes are pivotal for next-generation lithium-ion batteries due to their high capacity and energy density. However, their inherent sensitivity to environmental perturbations (e.g., air, electron beams) and dynamic structural degradation during the cycling process, such as Li/Ni cation disorder, microcrack propagation, and surface parasitic reactions, pose significant challenges for characterizing their authentic structural states. Conventional characterization techniques often introduce artifacts or fail to capture real-time degradation mechanisms under operating conditions. In this review, we systematically analyze the limitations of traditional characterizations and highlight the necessity of advanced non-destructive (e.g., cryo-electron microscopy), high-resolution (e.g., scanning diffraction X-ray microscopy), and in situ/operando techniques (e.g., operando neutron powder diffraction, in situ X-ray absorption fine structure spectroscopy) to address these challenges. Furthermore, we investigate the synergistic integration of machine learning, multimodal characterization techniques, and theoretical calculation to elucidate complex degradation mechanisms and expedite the rational design of stable Ni-rich cathode materials.