Construction of interfacial layer on microporous layer for enhancing gas diffusion electrode performance

Abstract

Enhancing the performance of gas diffusion electrodes (GDEs) is essential for their widespread application in proton exchange membrane fuel cells (PEMFCs). A critical factor that restricts performance enhancement is the insufficient protonic conductivity within GDE-based membrane electrode assemblies (MEAs). This study endeavored to boost GDE performance by constructing an interfacial layer on the microporous layer (MPL). Following the construction of this layer, the reduced pore size in the interfacial layer better maintains the structural continuity of the catalyst layer, enhancing proton conduction efficiency within the catalyst layer, and increasing the contact area between the catalyst layer and the proton exchange membrane (PEM). These results indicate enhanced protonic conductivity within the catalyst layer and between the catalyst layer and the PEM. Notably, the cell voltage achieved with the interfacial layer-enhanced GDE can reach 0.580 V at 2 A cm⁻², leading to a 10 % improvement over the original GDE. An investigation of the gas transport process revealed that increased protonic conductivity also reduced oxygen transport resistance within the catalyst layer. Furthermore, the composition of the interfacial layer significantly impacts fuel cell performance. Excessive ionomers tend to cause flooding in the catalyst layer, adversely affecting gas transport capability.