Imperfect Battery Materials: A Closer Look at the Role of Defects in Electrochemical Performance

Structural and compositional defects in crystalline materials are unavoidable. Accurately disentangling their role in composition–structure–property correlations is therefore essential but has long been hindered by our inability to precisely identify and quantify certain microstructural features. As a result, deviations from ideal structures have frequently been disregarded or assumed to be detrimental. Nonetheless, today's structural disorder characterization advancements offer unprecedented insights into defect architectures. Recent models and tools applied to scattering and spectroscopic techniques provide an accessible window for observing and accurately parametrizing microstructural complexity and, if understood and mastered, offer the utmost control for designing better materials. One important field that can greatly benefit from advancement in the understanding and control of structural defects is the development of battery materials, whose performance and cycle life are closely related to structural aspects, including defects. This perspective offers an overview of the progress achieved in this field, with a special focus on cathode materials, and a discussion about opportunities for future developments.