Redox‐Active Inorganic Materials for Redox Flow Batteries

Abstract

AbstractContinuous growth in utilization of renewable but intermittent energy such as solar and wind will accelerate the demand for grid‐scale energy storage systems. Redox flow batteries (RFBs) have been intensively studied for large‐scale energy storage (MW/MWh), which is particularly attractive when integrated with renewable energy sources. In past decades, extensive efforts have been made to improve electrochemical performance of the RFBs by exploring various active materials, from inorganic redox‐active materials to organic redox‐active molecules. Compared to burgeoning organic RFBs, inorganic RFBs have received extensive research and development in the last several decades. A great deal of efforts has been exerted to commercialize several inorganic RFB systems such as all‐vanadium RFBs and zinc–bromine RFBs. In this article, inorganic redox‐active materials (e.g., metal salts, halides, polysulfides, polyoxometalate (POM), etc.) applied in RFBs are reviewed with a primary focus on their most recent technological advances in aqueous inorganic RFBs. The advantages and limitations of different inorganic RFBs are discussed. Further technological challenges and perspective on inorganic RFBs are also highlighted.