Taurine Electrografting onto Porous Electrodes Improves Redox Flow Battery Performance

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Porous carbonaceous electrode surface properties critically impact redox flow battery (RFB) performance, durability, and cost.
• Current carbon fiber electrodes exhibit limited kinetic activity and wettability, hindering RFB efficiency.
• Conventional surface treatments lack precise control over desired functional properties.

Purpose of the Study:

• To introduce electrografting as a facile, rapid, and versatile technique for task-specific functionalization of carbonaceous electrodes for RFBs.
• To investigate the efficacy of taurine electrografting for enhancing electrode performance in aqueous RFBs.

Main Methods:

• Electrografting using cyclic voltammetry to covalently attach taurine molecules to carbon cloth electrodes.
• In situ polarization and impedance spectroscopy to evaluate electrochemical performance.
• Operando neutron radiography to assess electrode wettability within a flow cell.

Main Results:

• Taurine-treated electrodes exhibited 40% lower charge transfer and 25% lower mass transfer resistances compared to untreated electrodes.
• Electrode interfaces demonstrated significantly faster Fe³⁺ reduction kinetics, with 2-fold and 4-fold higher current densities than oxidized and untreated glassy carbon.
• Improved mass transfer was attributed to superior wettability of taurine-functionalized electrodes.

Conclusions:

• Electrografting provides a highly effective method for tailoring carbon electrode surfaces for RFBs.
• Taurine functionalization enhances both kinetic activity and mass transport, leading to improved RFB performance.
• This technique holds promise for optimizing electrodes in various RFB chemistries and other electrochemical technologies.