Engineered Membrane–Electrode Interface for Hydrocarbon-Based Polymer-Electrolyte-Membrane Fuel Cells via Solvent-Vapor-Annealed Deposition

Abstract

We present a facile and simple method to fabricate a three-dimensional (3D) interface between a hydrocarbon-based polymer membrane and an electrode of a membrane–electrode assembly via solvent-vapor-annealed deposition (SVAD). SVAD not only increases the membrane proton conduction with nanophase-separated morphology but also reduces the interfacial resistance between the membrane and electrode with formation of nanoscale 3D interfaces. The enlarged interfacial area improves the power performance of fuel cells, originating from reduced interfacial resistances and increased electrochemical active surface area of the catalyst layer (CL) by ionomer impregnation into the tortuous nanopores of the nearest CL. Furthermore, the effect of the engineered 3D interface is investigated by measuring the mechanical durability by the wet–dry cycle and peel strength.

A Novel Approach to Fabricate Membrane Electrode Assembly by Directly Coating the Nafion Ionomer on Catalyst Layers for Proton-Exchange Membrane Fuel Cells

“…Nevertheless, delamination, which can increase the resistance of MEA including ohmic resistance, charge-transfer resistance, and mass transport resistance, has seriously detrimental impacts on the cell performance. ,, For the N-MEA and N-R-MEA (Figure S1b,c), delamination is not observed between the membrane and the CLs. This fact illustrates that the ionomer solution can penetrate into the catalyst layer structure, enhancing the interfacial connection between the membrane and the CLs, which will, in turn, improve charge transfer and ionic conduction between the CLs and the membrane. , As seen in Figure e, the membrane thickness of the N-MEA is measured to be about 18 μm, which is comparable with the thickness of the C-MEA (16 μm, Figure d). It is also observed from Figure S1e that the N-R-MEA surface is very smooth and uniform, indicating that the ionomer is well filled into the pores of ePTFE.…”

“…Meanwhile, the existence of delamination in the conventional C-MEA could lead to a dead zone due to the lack of reactant, which will further bring a loss of apparent catalytic activity. By coating the ionomer onto the CLs, the ionomer penetrates into the macropores of the cracks in the N-MEA and N-R-MEA, which can improve the Pt catalyst utilization through improving proton conduction and enhancing TPB …”

“…However, the N-R-MEA shows lower R ct and R mt . This could attribute to the formation of ionic conduction hydrophilic polymer channels in the CLs, which facilitates proton diffusion and maximizes the TPB . An excellent interfacial connection between the membrane and CLs also contributes to lower R ct and R mt for the N-R-MEA …”

“…Several approaches have been reported to reduce the interfacial resistance between the PEM and CLs. − For instance, Oh and Bae fabricated a three-dimensional (3D) interface between a hydrocarbon-based polymer membrane and an electrode via solvent-vapor-annealed deposition (SVAD), not only increasing the membrane proton conduction with nanophase-separated morphology but also reducing the interfacial resistance between the PEM and electrode with nanoscale 3D interfaces formed. However, this SVAD method uses poisonous polar organic solvents like dimethyl sulfoxide (DMSO) and the long annealing time is limited to laboratory-scale research.…”

All‐Hydrocarbon MEA for PEM Water Electrolysis Combining Low Hydrogen Crossover and High Efficiency

“…While for PEM fuel cells there is extensive literature on hydrocarbon membranes [ 7–12 ] and hydrocarbon electrodes, [ 13 ] similar studies in the field of PEM water electrolyzers (PEMWEs) are still missing despite the aforementioned advantages. Especially their gas tightness is of high importance, since PEMWEs are often operated at high pressures [ 14 ] and critical contents of hydrogen in oxygen can be easily reached, forcing a system to shut down.…”