Oxygen Vacancy Modulation towards High‐Performance Layered Oxide Cathodes for Lithium/Sodium‐Ion Batteries

Abstract Oxygen vacancies (Vo) as a common structural defect play a critical and fascinating role in regulating the physico‐chemical properties of metal oxides. For the layered transitional‐metal oxides (LTMOs) used as the popular cathodes for lithium/sodium‐ion batteries (LIBs or SIBs), Vo can modulate their intrinsic multi‐scale structural properties, thereby significantly affecting the final electrochemical performance. In this concept article, we summarize the fundamental structural regulation mechanisms of Vo in lithium/sodium‐based LTMOs in terms of ligand, local, and crystal structures. Finally, the current challenges and outlooks of Vo engineering are highlighted for future development of high‐performance layered oxide cathode materials.