Recent Progress in the Emerging Modification Strategies for Layered Oxide Cathodes toward Practicable Sodium Ion Batteries

Low‐cost sodium‐ion batteries (SIBs) have been extensively considered as a supplement or even a replacement for successful lithium‐ion batteries. However, the practical application of SIBs is limited by their energy density and cyclic performance, which are mainly constrained by the cathode side. Therefore, the development of advanced cathode materials is essential for the practical application of SIBs. Among the various cathode materials, layered transition metal oxides (LTMOs) are highly promising candidates due to their compact crystal structure, low‐cost, ease of preparation, and similarities to successful Li‐based LTMOs. Unfortunately, the bottleneck issues faced by Na‐based LTMOs, such as severe phase transitions, sluggish diffusion kinetics, and interface deterioration, pose significant challenges in achieving high‐performance cathodes. In this review, a comprehensive overview and summary of recently reported modification strategies for layered oxides are provided and the structure–function–performance relationship is refined. A perspective on the outlook and development direction for Na‐based LTMOs cathodes is also provided. This review comprehensively explores the modification strategies of Na‐based LTMOs, providing a new horizon for future research on Na‐based LTMOs. The recent advances in modification strategies of layered transition metal oxides for sodium ion batteries including ion doping, morphological manipulation, interface engineering, and integrated tactics are comprehensively overviewed and summarized. A perspective on the future development of Na‐based layered transition metal oxides is presented. This review is expected to provide a new avenue for designing layered cathodes.