Redox flow batteries (RFBs) work by storing energy in liquid electrolytes, which flow through the electrochemical cell. Two separate tanks store these electrolytes, which contain dissolved electroactive species. With the use of pumps and pipes, these species circulate between the tanks and the cell. In the cell, electrochemical reactions occur – oxidation (loss of electrons) on the anode and reduction (gain of electrons) on the cathode. The two electrolytes are separated with an ion exchange membrane, which allows maintenance of charge balance.
RFBs typically use porous carbon-based electrodes as anodes and cathodes. Carbon felt (Figure 1) is commonly used. These electrodes provide a high surface area for electrochemical reactions and enable electrolyte flow through its pores. Advanced design of RFBs includes surface treatments to modify the carbon electrodes in order to enhance electrode reaction kinetics and electrolyte wettability. Heat or chemical treatments, plasma or electrochemical modifications are commonly used.
In BatCAT project, we are studying vanadium based redox flow batteries, which employ vanadium ions in different oxidation states as the electroactive material. Specifically, the focus is on understanding how the surface modification manufacturing step influences the performance of RFBs.
Sara Drvarič Talian, NIC
May 2025