Rechargeable iron-ion (Fe-ion) batteries: recent progress, challenges, and perspectives

With the ever-increasing demand for efficient and sustainable energy solutions, rechargeable Fe-ion batteries have emerged as a viable alternative to conventional rechargeable batteries. Rechargeable Fe-ion batteries are considered one of the most promising energy storage devices due to their low cost, abundance, eco-friendliness, and enhanced safety. This review article provides an in-depth overview of the essential components, such as electrodes and electrolytes, for all Fe-ion-based rechargeable batteries and emphasizes their distinctive features and potential advantages. Furthermore, it covers the current state of rechargeable Fe-ion batteries, highlighting recent advancements in electrode materials. It provides the details of recent findings on the electrochemical characteristics of rechargeable Fe-ion batteries, including their Fe-anode coulombic efficiency, capacity, cycling stability, and safety aspects for both aqueous and non-aqueous rechargeable Fe-ion batteries. It addresses the significance of various material innovations and engineering strategies to develop efficient electrode and electrolyte materials. It also highlights the current challenges for the cathode, anode, and electrolyte of rechargeable Fe-ion batteries, followed by their future perspectives. In conclusion, this review provides valuable insights into rechargeable Fe-ion batteries in a broader context for researchers to develop Fe-ion batteries as potential candidates for future energy storage technologies.