The Experts below are selected from a list of 93795 Experts worldwide ranked by ideXlab platform
Aimy Bazylak - One of the best experts on this subject based on the ideXlab platform.
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Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Nan Ge, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( −2 ), lower cathode RH levels resulted in the largest Oxygen Transport resistances due to reductions in ionomer hydration in the catalyst layer. In the intermediate current density range (1.5–2.1 A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
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liquid water saturation and Oxygen Transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
Daniel Muirhead - One of the best experts on this subject based on the ideXlab platform.
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Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Nan Ge, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( −2 ), lower cathode RH levels resulted in the largest Oxygen Transport resistances due to reductions in ionomer hydration in the catalyst layer. In the intermediate current density range (1.5–2.1 A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
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liquid water saturation and Oxygen Transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
Yu Morimoto - One of the best experts on this subject based on the ideXlab platform.
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humidity and temperature dependences of Oxygen Transport resistance of nafion thin film on platinum electrode
Electrochimica Acta, 2016Co-Authors: Kenji Kudo, Ryosuke Jinnouchi, Yu MorimotoAbstract:Abstract The Oxygen Transport resistances of Nafion thin films on a Pt electrode and of a bulk Nafion were evaluated to clarify the dominant part of the Oxygen Transport loss in an ionomer for a cathode catalyst layer of polymer electrolyte fuel cells. To evaluate the Oxygen Transport resistances of the Nafion thin film, an Oxygen flux through the Nafion thin film on the Pt was detected as diffusion limited current density, j d , for an Oxygen reduction reaction by using an electrochemical cell equipped with a Pt microelectrode coated with a Nafion film less than 100 nm. An interfacial Oxygen Transport resistance and inner resistivity of the Nafion thin film were separately determined by the relation between j d −1 normalized by Oxygen partial pressure and the film thickness. The interfacial resistance is equivalent to 30–70 nm of the Nafion film, which are much thicker than a typical ionomer thickness of ∼10 nm observed in catalyst layers. From the above results and our recent theoretical results obtained by molecular dynamics techniques, the Oxygen permeation fluxes through the ionomers in catalyst layers can be regarded as dominantly controlled by the Oxygen permeation at the Pt/ionomer interface.
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model for investigation of Oxygen Transport limitation in a polymer electrolyte fuel cell
Journal of Power Sources, 2013Co-Authors: Takahisa Suzuki, Kenji Kudo, Yu MorimotoAbstract:Abstract A model for Oxygen Transport in the catalyst layer of polymer electrolyte fuel cells was developed. The model includes Oxygen Transport resistance for dissolution from the gas phase into the ionomer, which is typically assumed to be negligible in conventional models. The dissolution kinetics were experimentally assessed by measuring the diffusion-limited current density, id, in a planar Pt electrode covered with thin ionomer films as a function of film thickness. The extrapolation of i d − 1 to zero thickness reflects the dissolution resistance. The effect of dissolution resistance is added to a conventional agglomerate model of the catalyst layer as an additional cause of Transport loss. The agglomerate size was determined so that the model predicted the same diffusion-limited current density as the experimental results. The agglomerate size was close to the particle size observed in scanning electron micrographs of the cross-section of the catalyst layer prepared by focused ion beam milling. In contrast, the conventional agglomerate model must adopt an agglomerate size that is larger by one order-of-magnitude than that experimentally observed. As a result, it is reasonable to attribute the hindrance of Oxygen Transport in the catalyst layer to the slow Oxygen dissolution at the gas–ionomer interface, rather than to the presence of large agglomerates.
Pranay Shrestha - One of the best experts on this subject based on the ideXlab platform.
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Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Nan Ge, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( −2 ), lower cathode RH levels resulted in the largest Oxygen Transport resistances due to reductions in ionomer hydration in the catalyst layer. In the intermediate current density range (1.5–2.1 A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
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liquid water saturation and Oxygen Transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
Rupak K Banerjee - One of the best experts on this subject based on the ideXlab platform.
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Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Nan Ge, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( −2 ), lower cathode RH levels resulted in the largest Oxygen Transport resistances due to reductions in ionomer hydration in the catalyst layer. In the intermediate current density range (1.5–2.1 A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
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liquid water saturation and Oxygen Transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers
Electrochimica Acta, 2018Co-Authors: Daniel Muirhead, Pranay Shrestha, Michael G. George, Jongmin Lee, Hang Liu, Rupak K Banerjee, Aimy BazylakAbstract:Abstract Liquid water accumulation in the gas diffusion layers (GDLs) of polymer electrolyte membrane (PEM) fuel cells is governed by a complex interplay of factors, the full scope of which is not yet fully established in literature. This study presents the combined effects of relative humidity (RH) and current density on liquid water accumulation and Oxygen mass Transport resistance in the cathode GDLs of a PEM fuel cell. Through-plane liquid water saturation distributions were measured in situ using synchrotron X-ray radiography while simultaneously performing limiting current-based characterizations of Oxygen Transport resistance. At low current densities ( A · cm − 2 ), high RH levels resulted in the largest Oxygen Transport resistances due to the observed significant sensitivity of liquid water accumulation to cathode RH. At high current densities (>3.0 A · cm − 2 ), cathode GDL liquid saturation levels were high regardless of cathode inlet RH, and the Oxygen Transport resistance was therefore less sensitive to RH. Furthermore, it was established that liquid water tends to preferentially accumulate in regions of higher local porosity within the GDL, identified by combining measured liquid water saturations with micro-computed tomography (μCT) characterizations of the through-plane porosity profile. Finally, the strong relationship between GDL Oxygen Transport resistance and liquid water-free (effective) pore space of the GDL was examined in order to consider the feasibility of predicting Oxygen Transport resistance based on overall liquid saturation.
