Layered Oxide Cathode Materials for Sodium-Ion Batteries: A Mini-Review

Layered transition metal oxides (LTMOs) are considered promising cathode materials for sodium-ion batteries (SIBs) due to their high specific capacity and low cost, making them promising candidates for commercialization. This review focuses on the current state of research on the structure and performance of LTMOs beginning with an explanation of the structure characteristics of P-phase and O-phase cathode materials. Next, to address the issues faced by LTMOs, including irreversible phase transitions during charge–discharge processes, the imbalance between energy density and cycling stability, and poor air stability, three modification strategies, such as element doping, surface coating, and structure design are summarized. Additionally, research on the complementary manganese and oxygen redox chemistry was also elucidated. Finally, an outlook on the development trends and application prospects of LTMOs is proposed, aiming to promote further fundamental research and practical application of SIBs.