Coaxial Nanowire Electrodes Enable Exceptional Fuel Cell Durability.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Conversion

Background:

• Polymer-electrolyte-membrane fuel cells (PEMFCs) are crucial for clean energy but face cost and durability challenges.
• Conventional PEMFC electrodes rely on platinum (Pt) nanoparticles on carbon supports, which are prone to degradation.
• Existing electrode designs limit Pt utilization and mass transport.

Purpose of the Study:

• To introduce a novel catalyst/electrode architecture for PEMFCs that overcomes limitations of conventional designs.
• To enhance the durability and efficiency of PEMFCs by eliminating degradation-prone components.
• To enable a paradigm shift in fuel cell electrode design for improved performance and commercialization.

Main Methods:

• Development of a coaxial nanowire electrode (CANE) architecture.
• Each nanowire features an ionomer core encapsulated by a nanoscale Pt film.
• Fabrication of membrane electrode assemblies (MEAs) utilizing the CANE architecture.

Main Results:

• The CANE architecture eliminates the triple-phase boundary, replacing it with double-phase boundaries for increased Pt utilization.
• CANEs demonstrated exceptional durability in accelerated stress tests (ASTs), with minimal performance loss (2% after 5000 support AST cycles, 5% after 30000 catalyst AST cycles).
• The new design eliminates the need for carbon supports and ionomer binders, improving mass transport and durability.

Conclusions:

• The CANE architecture offers a transformative approach to PEMFC electrode design, significantly improving durability.
• This innovation facilitates higher Pt utilization and faster mass transport, leading to high power density.
• CANEs represent a significant advancement towards the commercialization of fuel cells for transportation and clean energy applications.