Electrospun Micro Porous Layer for Enhanced Proton Exchange Membrane Water Electrolysis

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Current porous transport layers (PTLs) utilized in proton exchange membrane water electrolyzers (PEMWEs), suffer from limited interfacial contact area with the catalyst layer which reduces the performance. Although high anode catalyst loadings can mitigate this issue, it contradicts the objective of reducing the loading of precious metals in PEMWEs to lower costs. The combination of poor in-plane conductivity of the anode catalyst and the poor interfacial contact results in increased contact resistance and reduced catalyst utilization which leads to accelerated catalyst degradation due to non-uniform exposure to the applied voltage or current in the catalyst. Micro-porous layers (MPLs) can alleviate the interfacial contact problem. MPLs provide with high surface areas and low pore size, facilitating enhanced contact with the catalyst layer and improving catalyst utilization. Furthermore, the hierarchical MPL morphology can aid in efficient oxygen removal and enhanced water transport to the anode catalyst layer.In this study, titanium-based MPLs were fabricated via electrospinning employing a titanium precursor and a carrier polymer. Electrospun offers a superior control on the morphology of the resulting fibers. The electrospun fibers were subsequently calcined to yield TiO2 fibers, forming the MPL. The MPL was then integrated into a commercial felt based PTL substrate through hot-pressing and sintering to enhance the improved integration between the MPL and substrate. We will present the electrochemical performance evaluation including polarization curves, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry. Surface characterization of the MPL and catalyst layer surface was performed via scanning electron microscopy (SEM) and laser profilometry before and after electrolyzer testing.AcknowledgementThis research is supported by the U.S. Department of Energy (DOE) Hydrogen and Fuel Cell Technologies Office through the Hydrogen from Next-generation Electrolyzers of Water (H2NEW) consortium. Program manager Dave Peterson and Mackenzie Hubert.