Analysis of the Reaction Rates in the Cathode Electrode of Polymer Electrolyte Fuel Cells

This paper presents a one-dimensional (1D) theoretical study on the electrochemical phenomena in the cathode dual-layer electrode of polymer electrolyte fuel cells (PEFCs). Following our previous work on transport and electrochemical processes in single-layer cathodes [ Y. Wang and X. H. Feng , J. Electrochem. Soc. , 155 , B1289 (2008) ], we extend the analysis to dual-layer catalyst layers, where the electrode is characterized by a two-layer configuration with specific properties assigned to each layer. A 1D model is developed, and explicit solutions are obtained for the profiles of the reaction rate and electrolyte phase potential across the dual-layer electrode. Effort is also made to analyze the solutions to explore the impacts of each layer's properties on their performance (i.e., the average reaction current in each layer) with particular focus on the ratios of the ionic conductivity (related to the ionomer content), specific area, and exchange current density (related to Pt loading and reaction interface roughness). The results can be applied to optimize electrode performance through dual-layer configuration for high-performance cost-effective electrodes for PEFCs.