Superhydrophobic flow channel surface and its impact on PEM fuel cell performance

Wang, Yongxin; Shakhshir, Saher Al; Li, Xianguo; Chen, Pu

doi:10.1093/ijlct/cts069

Cited by 18 publications

(5 citation statements)

References 70 publications

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“…Previous studies have found that the static contact angle alone is not sufficient to represent the surface dynamic wettability behavior for the description of the liquid water movement on the surface . In a recent study, hydrophobic surfaces were prepared by using the poly(dimethylsiloxane)/silica coatings . It was found that easier water movement on the surface was obtained as the size of the silica particle in the coating material was increased, although the static contact angles measured on the solid surface with different coatings were almost the same.…”

Section: Introductionmentioning

confidence: 99%

“…It was found that easier water movement on the surface was obtained as the size of the silica particle in the coating material was increased, although the static contact angles measured on the solid surface with different coatings were almost the same. Therefore, sliding angle is another parameter for the description of the surface dynamic wettability associated with the water transport on the surface . As shown in Figure B, the sliding angle is normally measured as the angle of the surface inclination at which liquid starts to slide on the surface under gravity, and it represents relative easiness of a liquid droplet moving on a surface under a driving force.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of liquid water transport in a proton exchange membrane fuel cell gas flow channel with dynamic wettability

Qin

Yin

2018

Int J Energy Res

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Summary Liquid water transport in the gas flow channel is significantly important for the water removal and management in proton exchange membrane fuel cells. Previous numerical studies consider a single and constant static contact angle for the liquid water transport on the channel surface, which is insufficient to account for the dynamic wettability behavior of the flow. In this study, a dynamic wettability model is developed that incorporates the sliding angle and dynamic contact angles for the simulation of water transport in the flow channel. It is found that both the sliding and dynamic contact angles have significant impact on the characteristics of the water transport and dynamics in the flow channel. Water spreading on the channel surface is elliptic, and its minor and major axes oscillate out of phase with the droplet height. The pressure loss for the 2‐phase flow in the channel is directly related to this oscillation and deformation of the droplet shape. Flow channel surface with a small sliding angle facilitates the water transport and removal and reduces the associated pressure loss in the channel. The conventional static wettability model would overpredict droplet deformation and breakup as well as the pressure loss in the channel.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling of liquid water transport in a proton exchange membrane fuel cell gas flow channel with dynamic wettability

Qin

Yin

2018

Int J Energy Res

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“…Interestingly, the published reports on the channel surface have shown that either hydrophilic or hydrophobic modifications can improve water management for PEMFCs, but their intrinsic mechanisms are quite opposite. − It has been demonstrated that the hydrophobic surface is beneficial to water removal in the channel of the bipolar plate because of lower adhesion and greater gas shearing. Wang et al have reported two kinds of surfaces on graphite channels, which are coated with superhydrophobic silica/polydimethylsiloxane composites or superhydrophilic silica. The results show that the superhydrophobic surface has lower adhesion to water, leading to easier water removal.…”

Section: Introductionmentioning

confidence: 99%

A Triple Bioinspired Surface Based on Perfluorodecyl Trimethoxysilane-Coated ZnO Nanosheets for Self-Driven Water Transport in a Flow Channel

Liu

Zhao

Fan

et al. 2022

ACS Appl. Nano Mater.

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Water management is important for the bipolar plates of proton-exchange membrane fuel cells (PEMFCs), and active drainage is a desirable feature for the design of bipolar plate channels. Herein, inspired by natural micro-nanostructures, a triple bioinspired surface has been fabricated, which combines the advantages of both superhydrophobic and superhydrophilic surfaces. The superhydrophobic surface (FZnO@CA-GS) is prepared by PFTS (perfluorodecyl trimethoxysilance) coating on ZnO nanosheet-decorated arrays of microscale cylinders manufactured by photolithography, and second-round photolithography is used to convert the superhydrophobic surface into a surface with wedged superhydrophilic patterns (WSPs). Then, the water transport performance has been investigated for the WSP, where the square of the initial velocity of the droplet is found to be proportional to the wedge angle from both the theoretical calculation and experimental data. Subsequently, an index of the R value representing the flow state of droplets has been introduced to determine the optimal values for the geometrical parameters of triple-bioinspired surface (TBS) in flow channels. Such a triple bioinspired strategy affords a promising approach to fabricate bipolar plate channels with the function of self-driven water transport for PEMFC. The use of the R value in optimization may also offer insights into the design of other micro-nanostructures.

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“…Superhydrophobic surfaces are very suitable for use on stainless steel bipolar plates in low-temperature environments due to their unique properties, such as drag reduction [27,28], anticorrosion [29,30], anti-icing [31,32] and self-cleaning [33,34]. The bipolar plate of the superhydrophobic flow channel, under normal operating temperature conditions, can effectively promote the discharge of excess water in the gas diffusion layer and flow channel to improve cell performance [35,36,37]. Therefore, the hydrophobic properties of stainless steel bipolar plates are of great priority in a low-temperature environment.…”

Section: Introductionmentioning

confidence: 99%

Study on the Properties of Vertical Carbon Nanotube Films Grown on Stainless Steel Bipolar Plates

Shi

Jin

et al. 2019

Materials

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Research on the conductivity and corrosion resistance of stainless steel bipolar plates in a proton exchange membrane fuel cell (PEMFC) is commonly performed in a normal-temperature environment (about 20 °C). However, these fuel cells must function in low-temperature environments (lower than 0 °C) in some conditions, such as in vehicle fuel cells and in portable power supplies that operate during the winter in northern China. Stainless steel bipolar plates have higher requirements in terms of their hydrophobic and anti-icing properties, in addition to needing high conductivity and corrosion resistance. In this study, carbon nanotubes (CNTs) are grown on the surface of 304 stainless steel (304 SS) without a catalyst coating by plasma-enhanced chemical vapor deposition (PECVD), which is a simple and cheap method that allows stainless steel to be used as bipolar plates in low-temperature environments. The Raman spectroscopy and scanning electron microscopy (SEM) results show that the CNTs grown on the surface of 304 SS have different morphologies. The stainless steel samples with different CNT morphologies are tested by hydrophobicity and in situ icing experiments to prove that vertical CNTs can achieve a superhydrophobic state and have good anti-icing properties. The interfacial contact resistance (ICR) of the bare 304 SS and the 304 SS with vertical CNTs is compared by voltammetry, and then the corrosion resistances of both types is compared in a simulated PEMFC environment via a three-electrode system. Consequently, the ICR of the 304 SS with vertical CNTs was lower than the bare 304 SS. The corrosion potential was positive, and the corrosion current density was greatly reduced for the stainless steel with vertical CNTs grown directly on its surface when compared with the bare 304 SS. The experimental results show that vertical CNTs have good application prospects as bipolar plates for PEMFCs in low-temperature environments.

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Superhydrophobic flow channel surface and its impact on PEM fuel cell performance

Cited by 18 publications

References 70 publications

Modeling of liquid water transport in a proton exchange membrane fuel cell gas flow channel with dynamic wettability

Modeling of liquid water transport in a proton exchange membrane fuel cell gas flow channel with dynamic wettability

A Triple Bioinspired Surface Based on Perfluorodecyl Trimethoxysilane-Coated ZnO Nanosheets for Self-Driven Water Transport in a Flow Channel

Study on the Properties of Vertical Carbon Nanotube Films Grown on Stainless Steel Bipolar Plates

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