Recent Advances and Future Perspectives of Membranes in Iron-Based Aqueous Redox Flow Batteries

Iron-based aqueous redox flow batteries (IBA-RFBs) represent a promising solution for long-duration energy storage, supporting the integration of intermittent renewable energy into the grid, thanks to their commendable safety profile and cost-effectiveness. Membranes, serving as pivotal components in redox flow batteries (RFBs), play a crucial role in facilitating ion conduction for internal circuit formation while preventing the crossover of redox-active species. Given their direct impact on RFB performance and cost, membranes merit considerable attention. This review provides an overview of recent advancements in membranes tailored for IBA-RFBs. Initially, it delineates the operational mechanisms of various IBA-RFB configurations. Subsequently, it delves into key performance metrics for evaluating membrane efficacy, dissecting the intricate interplay between membrane performance and overall IBA-RFB efficiency. Building upon this foundation, the review spotlights recent breakthroughs in ion exchange membranes and porous membranes designed specifically for IBA-RFBs, showcasing their remarkable ability to bolster battery efficiency, cycling stability, and cost-effectiveness. Lastly, this review outlines future directions for membrane development, offering some insights to propel the widespread adoption of IBA-RFBs on a large scale.