Challenges and Progress in Rechargeable Magnesium‐Ion Batteries: Materials, Interfaces, and Devices

Abstract Rechargeable magnesium‐ion batteries (RMBs) have garnered increasing research interest in the field of post‐lithium‐ion battery technologies owing to their potential for high energy density, enhanced safety, cost‐effectiveness, and material resourcefulness. Despite substantial advancements in RMB research, a number of intrinsic challenges remain unresolved, such as the strong Coulombic interaction between Mg 2+ and the host crystal structure of cathode materials, sluggish Mg 2+ diffusion kinetic, poor electrolyte compatibility, and the formation of passivation films on the Mg anode interface. These issues hinder the commercial applications of RMBs. This review provides a comprehensive overview of the progress in key areas of RMB research, including representative magnesium‐ion storage cathode/anode materials and magnesium‐ion conducting electrolytes. Additionally, recent developments in electrode‐electrolyte interface regulations and pouch‐cell fabrication are outlined, highlighting current challenges and the implementation of effective solutions. Finally, future research directions are proposed to guide the development of high‐performance RMBs with practical applications.