Pore Structure Optimization of the Cathode Catalyst Layer in Proton Exchange Membrane Fuel Cells via Oxalic Acid Dihydrate

In proton exchange membrane fuel cells (PEMFCs), the electrochemical reactions occurring in the cathode catalyst layer (CCL) play a decisive role, with oxygen transport resistance (OTR) remaining a critical factor influencing reaction kinetics. This study proposes the incorporation of oxalic acid dihydrate as a pore-forming agent into the conventional CCL to optimize pore structure distribution. The effects of varying pore-forming agent-to-catalyst ratios on cell performance are systematically investigated. Experimental results demonstrate that the pore-forming agent successfully constructs abundant pore channels within the CCL, reducing OTR. At a pore-forming agent-to-catalyst mass ratio of 4 ∶ 1 , the modified CCL achieves optimal performance, with current density increasing from 2,000 to 2,320 mA / cm 2 at 0.65 V, representing a 16% enhancement. Porosity analysis reveals that the introduction of pore-forming agents increases the overall porosity of the CCL and shifts the pore size distribution toward larger diameters, facilitating oxygen molecule diffusion. OTR measurements under dry conditions confirm a significant reduction in resistance, validating improved oxygen transport efficiency. Therefore, selecting appropriate pore-forming agents enables the construction of efficient pore structure channels in the CCL, thereby achieving high-power output in fuel cells.