Non-Solvent Induced Phase Separation Enables Designer Redox Flow Battery Electrodes

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Porous carbonaceous electrodes are critical for redox flow battery (RFB) performance, influencing efficiency, cost, and durability.
• Achieving high surface area, low pressure drop, and facile mass transport simultaneously is a major challenge in RFB electrode design.

Purpose of the Study:

• To introduce non-solvent induced phase separation (NIPS) as a versatile method for synthesizing tunable porous structures for RFB electrodes.
• To investigate how varying the ratio of polyacrylonitrile to poly(vinylpyrrolidone) affects electrode microstructure and porosity.

Main Methods:

• Non-solvent induced phase separation (NIPS) for electrode synthesis.
• Tomographic microscopy, porosimetry, and spectroscopy for structural and chemical characterization.
• Flow cell studies using all-vanadium and Fe2+/3+ redox couples.

Main Results:

• NIPS enables the synthesis of electrodes with distinct microstructures and tunable porosity.
• The novel electrodes demonstrated superior performance compared to traditional carbon fiber electrodes in flow cell tests.
• A bimodal porous structure with large macrovoids and smaller pores was identified as key to improved performance.

Conclusions:

• The NIPS approach offers a promising platform for developing advanced porous electrodes for electrochemical flow technologies.
• This method allows for the optimization of electrode properties to meet the demanding requirements of RFBs.
• The developed electrodes show potential for enhancing the efficiency and scalability of redox flow batteries.