Electrocatalysis at electrodes for vanadium redox flow batteries

Flow batteries (also: redox batteries or redox flow batteries RFB) are briefly introduced as systems for conversion and storage of electrical energy into chemical energy and back. Their place in the wide range of systems and processes for energy conversion and storage is outlined. Acceleration of electrochemical charge transfer for vanadium-based redox systems desired for improved performance efficiency of these systems is reviewed in detail; relevant data pertaining to other redox systems are added when possibly meriting attention. An attempt is made to separate effects simply caused by enlarged electrochemically active surface area and true (specific) electrocatalytic activity. Because this requires proper definition of the experimental setup and careful examination of experimental results, electrochemical methods employed in the reviewed studies are described first.