Chapter 14 - Advances in membrane and stack design of redox flow batteries (RFBs) for medium- and large-scale energy storage

Abstract

The redox flow battery (RFB) has received great attention due to its attractive features for large-scale energy storage applications. The membrane, especially the most commonly used ion-exchange membrane (IEM), is a key component in all RFBs; it prevents the cross-mixing of the positive and negative electrolytes while allowing transport of the charge-carrying ions during the charge-discharge process. Membranes currently determine the cost of RFB systems, since they make up the major component of the cost when compared to the other constituents such as the electrode and the electrolyte. Thus there is a need to develop cost-effective chemically stable membranes for RFBs. This chapter talks about the various membranes used in RFBs, IEMs in particular, their fabrication, properties, and their determination, their applications, and the extent of research and development involved particularly on vanadium redox flow batteries, which are the most promising amongst all redox flow battery systems. The development of nonionic membranes for RFBs is also discussed in this chapter.