Local Structural Distortions in Lithium-Ion Battery Electrodes: A Review of Mechanisms and Characterization Technique

The primary objective of this review is to provide a comprehensive understanding of local structural distortions in lithium-ion battery electrodes, elucidating their underlying mechanisms, impact on electrochemical performance, and the advanced characterization techniques used to probe them. Local structural distortions in lithium-ion battery electrodes critically influence electrochemical performance, including capacity retention, rate capability, and cycling stability. These distortions arise from a variety of mechanisms, such as lithium intercalation/deintercalation, cation disorder, lattice strain, and defect formation, and they play a decisive role in electrode degradation and performance limitations. This review provides a comprehensive examination of the origins and types of local structural distortions in commonly studied electrode materials, including layered oxides, spinels, and olivine-type compounds. We survey advanced characterization techniques, spanning X-ray and neutron diffraction, pair distribution function analysis, electron microscopy, nuclear magnetic resonance, and spectroscopic methods, emphasizing their ability to resolve local structural features beyond average crystallographic information. The review further highlights correlations between distortion phenomena and electrochemical properties, as well as strategies to mitigate structural degradation through compositional engineering and nano-structuring. By synthesizing recent experimental and theoretical insights, this work aims to provide researchers with an integrated understanding of local structural distortions and their implications for the rational design of high-performance lithium-ion battery electrodes.