Highly Stable Vanadium Redox-Flow Battery Assisted by Redox-Mediated Catalysis

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Vanadium redox-flow batteries (VRBs) are scalable electrochemical energy storage (EES) technologies.
• Traditional VRB electrodes (carbon, graphite felt) exhibit low electrochemical activity, leading to overpotential losses and reduced efficiency.
• Improving electrode performance is crucial for enhancing VRB efficiency and stability.

Purpose of the Study:

• To fabricate high-performance Prussian blue/carbon felt (PB/CF) composite electrodes for VRBs.
• To investigate the electrochemical activity and stability of PB/CF electrodes.
• To assess the potential of PB/CF electrodes for large-scale VRB applications.

Main Methods:

• Facile electrodeposition technique used to synthesize PB/CF composite electrodes.
• Electrochemical characterization of PB/CF electrodes for VO2+/VO2+ redox couple.
• Fabrication and testing of VRB cells and a three-cell stack using PB/CF electrodes.

Main Results:

• PB/CF electrodes demonstrated high electrochemical activity for the VO2+/VO2+ redox couple.
• VRBs with PB/CF electrodes achieved high average cell voltage efficiency (90%) and energy efficiency (88%) at 100 mA cm-2.
• PB/CF electrodes exhibited significantly improved long-term stability compared to pristine carbon felt electrodes.
• A three-cell VRB stack confirmed the reliability of PB/CF electrodes for scalable applications.

Conclusions:

• The facile electrodeposition of Prussian blue on carbon felt creates high-performance electrodes for VRBs.
• PB/CF electrodes offer enhanced electrochemical activity, efficiency, and stability, addressing limitations of traditional VRB electrodes.
• This work provides a promising pathway for designing advanced electrodes for commercial VRB systems.