A Molecular Model of PEMFC Catalyst Layer: Simulation on Reactant Transport and Thermal Conduction

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Proton exchange membrane fuel cells (PEMFCs) are crucial for clean energy.
• Minimizing platinum loading while maintaining high efficiency in the catalyst layer (CL) is a key challenge.
• Understanding interfacial interactions between carbon, platinum (Pt), and ionomer is vital for enhancing reaction efficiency.

Purpose of the Study:

• To clarify interfacial interactions within the three-phase interface of a PEMFC catalyst layer.
• To investigate the impact of water and ionomer content on transport phenomena and thermal conductivity.
• To provide insights for designing optimized catalyst layers with reduced platinum content and improved performance.

Main Methods:

• Development of a molecular model incorporating carbon, Pt, and ionomer.
• Application of equilibrium and nonequilibrium molecular dynamics (MD) simulations.
• Analysis of radial distribution functions (RDFs), diffusion coefficients, water cluster morphology, and thermal conductivity.

Main Results:

• Increased water content enhances water aggregation and interconnection, benefiting oxygen and proton transport.
• Higher ionomer content improves proton transport but impedes oxygen transport.
• Both water and ionomer content increases were found to improve the thermal conductivity of the catalyst layer.

Conclusions:

• Interfacial interactions significantly influence transport properties in PEMFC catalyst layers.
• Water and ionomer content are critical parameters for optimizing catalyst layer design.
• Findings guide the development of more efficient and cost-effective PEMFCs with reduced platinum usage.