Recent advances in conversion-type iron-based materials for sodium-ion batteries

Lithium-ion batteries have come to dominate the secondary energy storage market; however, their broader application is limited by the scarcity of lithium resources and high production costs. As a promising alternative, sodium-ion batteries (SIBs) have attracted significant attention due to their similar electrochemical behavior and the abundant availability of sodium-based raw materials. It is well recognized that the electrode material plays a crucial role as it directly influences the overall cycle life of the battery. Iron-based materials are particularly attractive due to their abundant raw material availability, cost-effectiveness, safety profile, and environmental friendliness; thus, they represent one of the most suitable classes of electrode materials. Recently, many studies have focused on designing appropriate nanostructures and developing straightforward methods for improving the electrochemical features of conversion-type iron-based electrodes. This review summarizes recent advancements in iron-based electrodes for SIBs and outlines future directions for the advancement of conversion-type iron-based materials. It is expected to provide valuable insights for the design of high-performance iron-based electrodes for SIBs.