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

Journal Article


Abstract


  • A significant and long-standing problem in

    electrochemistry has demanded the need for gas diffusion

    electrodes that are “flood-proof” and “leak-proof” when

    operated with a liquid electrolyte. The absence of a solution

    to this problem has, effectively, made it unviable to use gas

    diffusion electrodes in many electrochemical manufacturing

    processes, especially as “gas-depolarized” counter electrodes

    with significantly decreased energy consumption. In this work,

    Gortex membranes (also known as expanded PTFE or ePTFE)

    have been studied as novel, leak-proof substrates for gas

    diffusion electrodes [PTFE = poly(tetrafluoroethylene)]. We report the fabrication, characterization, and operation of gas

    diffusion electrodes comprising finely pored Gortex overcoated with 10% Pt on Vulcan XC72, PTFE binder, and a fine Ni mesh

    as a current carrier. Capillary flow porometry indicated that the electrodes only flooded/leaked when the excess of pressure on

    their liquid-side over their gas-side was 5.7 atm. This is more than an order of magnitude greater than any previous gas diffusion

    electrode. The Gortex electrodes were tested as hydrogen- and oxygen-depolarized anodes and cathodes in an alkaline fuel cell

    in which the liquid electrolyte was pressurized to 0.5−1.5 atm above the gas pressures. Despite the record high electrolyte

    pressure, the electrodes, which had Pt loadings of only 0.075 mg Pt/cm2

    , exhibited notable activity over 2 d of continuous, leakfree

    operation. Under the applied liquid pressure, the fuel cell also overcame all of the key technical challenges that have

    hindered the adoption of alkaline fuel cells to date. The high activity and unprecedented resistance to leaking/flooding exhibited

    by these electrodes, even when subjected to large liquid electrolyte overpressures under gas depolarization conditions, provide

    an important advance with far-reaching implications for electrochemical manufacturing.

Publication Date


  • 2018

Citation


  • Tiwari, P., Tsekouras, G., Swiegers, G. F. & Wallace, G. G. (2018). Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking. Acs Applied Materials & Interfaces, 10 (33), 28176-28186.

Scopus Eid


  • 2-s2.0-85050848920

Number Of Pages


  • 10

Start Page


  • 28176

End Page


  • 28186

Volume


  • 10

Issue


  • 33

Place Of Publication


  • United States

Abstract


  • A significant and long-standing problem in

    electrochemistry has demanded the need for gas diffusion

    electrodes that are “flood-proof” and “leak-proof” when

    operated with a liquid electrolyte. The absence of a solution

    to this problem has, effectively, made it unviable to use gas

    diffusion electrodes in many electrochemical manufacturing

    processes, especially as “gas-depolarized” counter electrodes

    with significantly decreased energy consumption. In this work,

    Gortex membranes (also known as expanded PTFE or ePTFE)

    have been studied as novel, leak-proof substrates for gas

    diffusion electrodes [PTFE = poly(tetrafluoroethylene)]. We report the fabrication, characterization, and operation of gas

    diffusion electrodes comprising finely pored Gortex overcoated with 10% Pt on Vulcan XC72, PTFE binder, and a fine Ni mesh

    as a current carrier. Capillary flow porometry indicated that the electrodes only flooded/leaked when the excess of pressure on

    their liquid-side over their gas-side was 5.7 atm. This is more than an order of magnitude greater than any previous gas diffusion

    electrode. The Gortex electrodes were tested as hydrogen- and oxygen-depolarized anodes and cathodes in an alkaline fuel cell

    in which the liquid electrolyte was pressurized to 0.5−1.5 atm above the gas pressures. Despite the record high electrolyte

    pressure, the electrodes, which had Pt loadings of only 0.075 mg Pt/cm2

    , exhibited notable activity over 2 d of continuous, leakfree

    operation. Under the applied liquid pressure, the fuel cell also overcame all of the key technical challenges that have

    hindered the adoption of alkaline fuel cells to date. The high activity and unprecedented resistance to leaking/flooding exhibited

    by these electrodes, even when subjected to large liquid electrolyte overpressures under gas depolarization conditions, provide

    an important advance with far-reaching implications for electrochemical manufacturing.

Publication Date


  • 2018

Citation


  • Tiwari, P., Tsekouras, G., Swiegers, G. F. & Wallace, G. G. (2018). Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking. Acs Applied Materials & Interfaces, 10 (33), 28176-28186.

Scopus Eid


  • 2-s2.0-85050848920

Number Of Pages


  • 10

Start Page


  • 28176

End Page


  • 28186

Volume


  • 10

Issue


  • 33

Place Of Publication


  • United States