Effects of the Structure, Wettability, and Rib-Channel Width Ratio on Liquid Water Transport in Gas Diffusion Layer Using the Lattice Boltzmann Method

Liao, Jiadong; Yang, Guogang; Shen, Qiuwan; Li, Shian; Jiang, Ziheng; Wang, Hao; Sheng, Zhonghua; Zhang, Guoling; Zhang, Hongpeng

doi:10.1021/acs.energyfuels.1c02023

Cited by 18 publications

(5 citation statements)

References 54 publications

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“…This is probably due to the water saturation level under ribs of the flow field (Figure b). Since the GDL under cold ribs had a large liquid water saturation level at low temperatures, , oxygen diffusion was hindered, resulting in increased R GDL . When GDLs were stacked in the cell, R GDL had little influence on the cell temperature (Figure c) because the thick GDL layer harvested the uniform gas supply to the CL, even if liquid water accumulated under cold ribs (Figure c).…”

Section: Resultsmentioning

confidence: 99%

Insights into Oxygen Transport Properties of Partially Saturated Gas Diffusion Layers for Polymer Electrolyte Fuel Cells

2023

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A multimodal approach was used to investigate the oxygen transport resistance of gas diffusion layers (GDLs) for polymer electrolyte fuel cells (PEFCs) under different temperature and humidity conditions. This study aimed to gain further insights into the oxygen transport properties of partially saturated GDLs by relating the GDL structure to water generation and transport. Morphological characterization of GDLs was performed by synchrotron X-ray computed tomography and mercury intrusion porosimetry. The oxygen transport resistance of dry and wet GDLs was measured directly using the Wicke-Kallenbach type diffusion cell. The observed transport properties of dry GDLs were correlated with the pore morphologies. Moreover, it was found that the direct measurement approach characterized the oxygen transport resistance of wet GDLs, eliminating the contribution of the catalyst-coated membrane, and captured the impact of water saturation level in GDLs on the oxygen transport properties. An electrochemical approach using limiting currents was used to study the effect of water generation on oxygen transport resistances. The oxygen transport resistance of wet GDLs at the PEFC cathode was evaluated by varying gas pressures and GDL thicknesses. Results show that the oxygen transport resistance of wet GDL depends on the local water saturation created by liquid water. Our comprehensive studies provide insights to derive the optimal evaluation method for a given purpose, leading to a rational and sustainable material design for GDLs of PEFCs.

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Section: Resultsmentioning

confidence: 99%

Insights into Oxygen Transport Properties of Partially Saturated Gas Diffusion Layers for Polymer Electrolyte Fuel Cells

2023

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“…A droplet of radius R is placed in the center of a 100 × 100 lu 2 square computational domain and the rest of the domain is filled with gas. The initial density is set as follows: the droplet region is set to ρ ai r = 1 × 10 −5 , ρ water = 2; the gas region is set to ρ water = 1 × 10 −5 , ρ air = 2 [ 50 , 51 ]. From the Young–Laplace law, it follows that the droplet will remain a steady circle under surface tension when the system reaches force equilibrium and that the pressure difference between the inside and outside of the droplet at a steady state satisfies the following relationship:

…”

Section: Numerical Approachmentioning

confidence: 99%

Effects of Compression and Porosity Gradients on Two-Phase Behavior in Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells

et al. 2023

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Water management within the gas diffusion layer (GDL) plays an important role in the performance of the proton exchange membrane fuel cell (PEMFC) and its reliability. The compression of the gas diffusion layer during fabrication and assembly has a significant impact on the mass transport, and the porosity gradient design of the gas diffusion layer is an essential way to improve water management. In this paper, the two-dimensional lattice Boltzmann method (LBM) is applied to investigate the two-phase behavior in gas diffusion layers with different porosity gradients under compression. Compression results in an increase in flow resistance below the ribs, prompting the appearance of the flow path of liquid water below the channel, and liquid water breaks through to the channel more quickly. GDLs with linear, multilayer, and inverted V-shaped porosity distributions with an overall porosity of 0.78 are generated to evaluate the effect of porosity gradients on the liquid water transport. The liquid water saturation values within the linear and multilayer GDLs are significantly reduced compared to that of the GDL with uniform porosity, but the liquid water within the inverted V-shaped GDL accumulates in the middle region and is more likely to cause flooding.

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“…According to Laplace’s law, the pressure difference between the inside and outside of a bubble and its radius of curvature satisfy the following relationship where Δ P is the pressure difference between the inside and outside of the bubble, R is the bubble radius, and σ denotes the surface tension coefficient. The pressure difference as a function of 1/ R is shown in Figure b.…”

Section: Numerical Approachmentioning

confidence: 99%

Pore-Scale Modeling of Mass Transport in Partially Saturated Cathode Gas Diffusion Layers of Proton Exchange Membrane Fuel Cell

Wang

Yang

et al. 2022

Energy Fuels

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Proton exchange membrane fuel cells (PEMFCs) have the advantages of high specific power, good stability, and zero emissions, making them clean and efficient energy conversion devices. Water management is one of the technical challenges limiting the development of PEMFC, with liquid water blocking the pores and increasing the resistance to mass transport. In this paper, a two-dimensional (2D) multiphase lattice Boltzmann (LB) model is developed to obtain the liquid water morphology within the gas diffusion layer (GDL). A 2D multicomponent flow Lattice Boltzmann model considering electrochemical reactions is established to investigate the effects of water saturation, activation overpotential, and pressure difference between the inlet and outlet gas channels on mass transport. At high water saturation, the liquid water forms water films within the GDL preventing reactive gas transport and water vapor are blocked near the catalyst layer making it difficult to remove. The PEMFC can achieve higher current densities at high activation overpotentials, but oxygen starvation will be exacerbated. Increasing the pressure difference between the inlet and outlet gas passages effectively increases the oxygen concentration and reduces the water vapor concentration in the GDL. The present study improves the understanding of the effect of GDL microstructure on mass transport and performance of PEMFC from the mesoscopic scale.

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Effects of the Structure, Wettability, and Rib-Channel Width Ratio on Liquid Water Transport in Gas Diffusion Layer Using the Lattice Boltzmann Method

Cited by 18 publications

References 54 publications

Insights into Oxygen Transport Properties of Partially Saturated Gas Diffusion Layers for Polymer Electrolyte Fuel Cells

Insights into Oxygen Transport Properties of Partially Saturated Gas Diffusion Layers for Polymer Electrolyte Fuel Cells

Effects of Compression and Porosity Gradients on Two-Phase Behavior in Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells

Pore-Scale Modeling of Mass Transport in Partially Saturated Cathode Gas Diffusion Layers of Proton Exchange Membrane Fuel Cell

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