Pathways to Widespread Applications: Development of Redox Flow Batteries Based on New Chemistries

Redox flow batteries (RFBs) stand out as one of the most promising candidates for stationary energy storage with high scalability and separate control over energy and power. Nevertheless, the widespread application of commercial RFBs is restricted by the relatively high stack cost as well as the uncompetitive performance metrics. Developing new-concept RFBs beyond conventional design frameworks can effectively alleviate these concerns. In this review, we aim to provide comprehensive fundamentals of new chemistries in RFBs toward widespread practical applications. We first introduce the technological features of conventional RFBs, followed by the specific cell architectures and possible optimization approaches on each component. We further review in detail the design principles and demonstrations of the newly developed RFBs, including novel redox species, integrated energy systems, and innovative cell structures. We conclude with a summary on the current challenges and future perspectives in this research field.