All-iron redox flow batteries : Working principle and recent developments

Abstract

All-iron redox flow batteries (AIRFBs) are a promising energy storage solution due to their low cost, safety, and abundance of raw materials. Their ability to decouple energy capacity from power output makes them highly scalable for grid applications. Traditional AIRFBs, however, face challenges such as limited charge-discharge depth, hydrogen evolution, and membrane selectivity issues, which hinder their commercial adoption.

Recent developments in electrolyte formulations, electrode engineering, and membrane technologies have improved efficiency, cycle life, and cost-effectiveness. The introduction of all-soluble AIRFBs (ASAI-AIRFBs) has further enhanced system stability by eliminating solid-phase deposition, improving electrolyte utilization, and increasing energy density. Additionally, innovative additives like 1-ethyl-3-methylimidazolium chloride (EMIC) have demonstrated enhanced electrolyte stability and reduced unwanted side reactions, contributing to long-term operational reliability.

This thesis provides a review of the working principles of AIRFBs, key technological advancements, and ongoing challenges in the field. The study also highlights the potential integration of AIRFBs with renewable energy sources, addressing their role in facilitating sustainable energy storage solutions [1]