Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Gas diffusion electrodes are crucial for electrochemical manufacturing but suffer from flooding and leaking issues with liquid electrolytes.
• This limits their use, particularly as energy-saving gas-depolarized counter electrodes.
• Existing solutions have not adequately addressed these operational challenges.

Purpose of the Study:

• To develop novel, leak-proof substrates for gas diffusion electrodes.
• To investigate the performance of Gortex (expanded PTFE) membranes in gas diffusion electrodes.
• To overcome limitations in electrochemical manufacturing and alkaline fuel cell adoption.

Main Methods:

• Fabrication of gas diffusion electrodes using Gortex membranes, platinum on Vulcan XC72, PTFE binder, and a nickel mesh current carrier.
• Characterization using capillary flow porometry to determine flooding and leaking pressure thresholds.
• Testing electrodes as hydrogen- and oxygen-depolarized anodes and cathodes in an alkaline fuel cell under pressurized electrolyte conditions.

Main Results:

• Gortex electrodes demonstrated unprecedented leak-proof and flood-proof performance, withstanding liquid-side overpressures up to 5.7 atm.
• Electrodes exhibited notable activity over 2 days of continuous, leak-free operation in an alkaline fuel cell with pressurized electrolyte.
• Key technical challenges hindering alkaline fuel cell adoption were overcome under applied liquid pressure.

Conclusions:

• Gortex membranes offer a viable solution for creating robust, leak-proof gas diffusion electrodes.
• These electrodes significantly advance the potential for gas-depolarized electrochemical manufacturing processes.
• The findings have far-reaching implications for improving the efficiency and viability of fuel cells and electrochemical processes.