Layered <i>3d</i> Transition Metal‐Based Oxides for Sodium‐Ion and Lithium‐Ion Batteries: Differences, Links and Beyond

Abstract Due to their stable crystal framework, promising energy density, and structural versatility, layered 3 d transition metal oxides have emerged as the preferred cathodes for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). While extensive research has individually addressed the lithium and sodium 3 d transition metal layered oxides, the differences and interconnections between the two types of materials have largely been overlooked. Effectively utilizing these summaries is essential for driving innovative structural designs and inspiring new insights into the structure‐property relationships. This review comprehensively bridges this gap by meticulously examining the disparities and links in the behavior of the layered oxides upon Li + and Na + storage and transfer. Key aspects, including atomic and electronic structure, phase transition mechanisms, charge compensation mechanisms and electrochemical kinetics, are carefully summarized. The implications of these aspects on the battery cycle life, energy density, and rate capability are thoroughly discussed. Additionally, by leveraging the unique characteristics of each oxide structure, this review explores the interconnection between lithium and sodium layered oxides in depth. Finally, a concise perspective on future targets and direction of 3 d layered oxides is deduced and proposed.