Materials and Devices for Iron Batteries: Recent Progress and Perspectives

The pursuit of carbon neutrality necessitates large-scale integration of intermittent renewable energy sources, driving the demand for electrochemical energy storage systems with high capacity, low cost, and intrinsic safety. While conventional lithium-ion and sodium-ion batteries currently dominate the market, their scalability is constrained by safety concerns and resource limitations. In this context, multivalent metal-ion systems (Al, Mg, Zn, and Fe) have emerged as promising alternatives. Among these, rechargeable iron-based batteries stand out due to Earth-abundant iron reserves, cost-effectiveness, exceptional volumetric capacity (7,550 mAh cm–3), environmental benignity, and inherent safety, positioning them as one of the most viable candidates for future energy storage. This review systematically examines recent advancements in Fe-based battery technologies, encompassing cathode material intercalation mechanisms, electrolyte formulation optimization, and architectural innovations. Furthermore, it critically evaluates the potential and limitations of emerging iron-centric electrochemical systems, including iron–organic complexes, iron–iodine redox couples, and iron–sulfur multielectron redox reactions, which represent cutting-edge directions in the field. The discussion extends to advanced strategies for mitigating challenges, such as anode passivation and capacity fade. In conclusion, this comprehensive analysis provides valuable insights into the development of Fe-ion batteries as next-generation energy storage solutions. By contextualizing technical progress within broader energy transition frameworks, this review offers a roadmap for researchers to address existing bottlenecks and accelerate the practical implementation of sustainable iron-based electrochemical systems.