Kim, B.-S.; Park, J.-H.; Park, J.-S. Effect of Blended Perfluorinated Sulfonic Acid Ionomer Binder on the Performance of Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells. Membranes2023, 13, 794.
Kim, B.-S.; Park, J.-H.; Park, J.-S. Effect of Blended Perfluorinated Sulfonic Acid Ionomer Binder on the Performance of Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells. Membranes 2023, 13, 794.
Kim, B.-S.; Park, J.-H.; Park, J.-S. Effect of Blended Perfluorinated Sulfonic Acid Ionomer Binder on the Performance of Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells. Membranes2023, 13, 794.
Kim, B.-S.; Park, J.-H.; Park, J.-S. Effect of Blended Perfluorinated Sulfonic Acid Ionomer Binder on the Performance of Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells. Membranes 2023, 13, 794.
Abstract
The blended perfluorinated sulfonic acid ionomers are prepared to have equivalent weight (EW) ~1000, 980, and 830. The catalyst layers (CLs) using blended PFSA ionomers with different side chain lengths and EWs are investigated, compared to the CLs utilizing single ionomers. The IEC results indicate that the blended ionomers have the targeted EWs. As a result, it is found that the blended ionomers exhibit higher ion conductivity than the single ionomers at all temperatures due to higher water uptake of the blended ionomers. Even though they have a similar EW, it implies that the blended ionomers have bulk structure to form competent free volume. The blended ionomers with short side chain (SSC) and low EW can help reduce the activation energy due to the enhanced hydrophobic and hydrophilic segregation. In addition, it is observed that the catalyst layers using the blended ionomer form more porous microstructure to help reduce the resistance of oxygen transport and attributes to lower mass transfer loss. This effect is significantly revealed in the fuel cell operation at not the lower temperature (70 °C) and full humidification (100%) but the elevated temperature (80 °C) and lower relative humidity (50 and 75%). The blended ionomer-based catalyst layers with higher water uptake and porous CL structure result in higher fuel cell performance and better mass transport than the single ionomer-based catalyst layers.
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