Fabrication of Nafion membranes with patterned microwire arrays and fuel cell performances
Due to the planar surface structure inherent in commercial Nafion membranes,the interface contact area between the membrane and catalyst layer is limited,resulting in a mere 25%—35%utilization rate of Pt-based catalysts in PEMFCs.To enhance the utilization efficiency of Pt-based catalysts,the inspiration from the naturally occurring hierarchical structures found on lotus leaves was drawn.In this study,these microstructures as templates to create patterned microwire arrays were employed.The surface microstructure of lotus leaves was first meticulously by using a PDMS casting agent replicatedby.Subsequently,this distinctive textured surface of lotus leaves was accurately transferred onto the Nafion membranes.This process yielded patterned microwire arrays with average diameters of(5.89±1.45)μm and(6.95±1.70)μm,respectively.Through meticulous optimization,the performance of the membrane electrode assembly(MEA)was significantly improved.Notably,the maximum power density increased from 0.625W/cm2 to 0.757W/cm2.These patterned microwire arrays augmented the surface hydrophobicity of the Nafion membrane,thereby enhancing mass transfer efficiency and reducing the reaction/internal resistance within the MEA.To probe the impact of these patterned microwire arrays on Pt catalyst utilization,the cyclic voltammetry was employed.This analysis revealed a 151%increased in the electrochemical surface area(ECSA)and a 43.4%of Pt utilization rate.In summary,the fabrication of patterned microwire arrays on Nafion membrane surfaces facilitated the formation of a three-phase interface for electrons,protons and reactants,improving the interface structure between the Nafion membrane and catalytic layer,and ultimately leading to a marked improvement in Pt utilization rate.
Nafion membranemicrowire arraymass transfer enhancementfuel cell
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维普
