A New Electrode Paradigm Enabled by Co-Axial Electrospinning

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Conventional polymer electrolyte membrane fuel cell (PEMFC) electrodes face challenges in balancing proton and oxygen transport.
• Ionomers in electrodes must facilitate proton conduction while allowing oxygen diffusion, creating conflicting material requirements.

Purpose of the Study:

• To introduce a novel co-axial electrospun electrode architecture for PEMFCs.
• To decouple proton and oxygen transport pathways for independent optimization.
• To establish a versatile platform for advanced electrochemical applications.

Main Methods:

• Fabrication of co-axial electrospun fibers with a pristine ionomer core and a multifunctional platinum-carbon-ionomer shell.
• Microscopy to confirm the core-shell fiber structure.
• Electrochemical impedance spectroscopy and limiting-current diagnostics to quantify performance.

Main Results:

• The co-axial electrospun electrode architecture successfully decouples proton and oxygen transport.
• Microscopy confirmed the distinct core-shell structure of the electrospun fibers.
• Performance metrics met or exceeded conventional electrodes at relative humidities above 75% due to enhanced non-Fickian diffusion.

Conclusions:

• Co-axial electrospun electrodes offer a versatile platform for advanced PEMFCs.
• This architecture enables independent tuning of core and shell properties.
• The technology shows promise for diverse electrochemical applications like CO2 electrolysis and water electrolysis.