Hierarchically conductive electrodes unlock stable and scalable CO₂ electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical CO2 reduction is a key technology for CO2 utilization.
• Gas Diffusion Electrodes (GDEs) are crucial for maximizing performance.
• Existing GDEs face tradeoffs between hydrophobicity (water resistance) and conductivity.

Purpose of the Study:

• To develop a novel electrode architecture that overcomes the limitations of current Gas Diffusion Electrodes.
• To enable scalable and efficient electrochemical CO2 reduction.
• To improve performance by addressing ohmic losses and flooding.

Main Methods:

• Development of a hierarchically conductive electrode architecture with interwoven microscale conductors within an expanded Polytetrafluoroethylene membrane.
• Modeling of spatial voltage and product distribution variability due to ohmic losses.
• Rational design of the electrode architecture based on the developed model.

Main Results:

• Demonstration of a scalable electrode architecture applicable to various catalysts.
• Achieved C2+ Faradaic efficiencies of approximately 75%.
• Reduced cell voltage by up to 0.9 V for electrodes up to 50 cm2.

Conclusions:

• The hierarchically conductive electrode architecture successfully overcomes scaling limitations in Gas Diffusion Electrodes.
• This design offers a pathway to more efficient and practical electrochemical CO2 reduction systems.
• The developed model provides a tool for rational electrode design, independent of catalyst specifics.