Optimizing the hydrophobicity of GDL to improve the fuel cell performance

Zhou, Ke; Li, Tianya; Han, Yuanjia; Wang, Jihao; Chen, Jia; Wang, Kejian

doi:10.1039/d0ra09658j

Cited by 27 publications

(9 citation statements)

References 31 publications

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“…An average output voltage of 5 V was obtained even under high 75% RH condition, as shown in Figure . Interestingly, it is clear that the developed device has maintained the output performance and still has ability to generate output voltage of 8 V even under 60% RH condition, which may arise due to the increase in the hydrophobicity cause by upward force generated by the air inside PVDF-CNT pores, lifting water droplets. − A small decrease in the output voltage under very high 75% RH may be attributed to the dissipation of piezoelectric charge build-up owing to the development of a water layer on the PVDF film. To confirm the hydrophobic nature of the device, surface contact angle is examined.…”

Section: Resultsmentioning

confidence: 98%

“…It has been obtained that the contact angle of PVDF-CNT foam was about 139°. The large value of the contact angle is because of the foam like structure. − The overhang foam structure along with CNT plays a key role in the enhancement of the hydrophobicity due to large surface area (Wt < Wb) even under pressure and thus high output voltage even under high humid condition is observed from the developed flexible nanogenerator (Figure c,d) . The output performance of the PVDF-CNT based nanogenerator device was compared to the recently reported PVDF based nanogenerators.…”

Section: Resultsmentioning

confidence: 98%

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Humidity Sustainable Hydrophobic Poly(vinylidene fluoride)-Carbon Nanotubes Foam Based Piezoelectric Nanogenerator

Badatya

Bharti

Sathish

et al. 2021

ACS Appl. Mater. Interfaces

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Light weight lead free, polymer, and carbon nanotubes based flexible piezoelectric nanogenerators have prompted widespread concern for harvesting mechanical energy and powering next generation electronics devices. Herein, lightweight polyvinylidene fluoride (PVDF)-carbon nanotube (CNT) foam was prepared to fabricate humid resistant hydrophobic flexible piezoelectric nanogenerator to converts mechanical energy into electricity for the first time. Hydrophobic piezoelectric PVDF-CNT foam with density of 0.15 g/cm3 was prepared by solution route. PVDF-CNT foam exhibited crystalline and a well-defined chain likes structure with 65% fraction of β-phase. Self-poled PVDF-CNT foam shows piezoelectric charge coefficient (d33) of 9.4 pC/N. High d33 of PVDF-CNT foam is caused by dipole alignment induced by local electric field of CNT in the microcellular structure of PVDF. The developed foam exhibits ultrahigh dielectric constant (ε′) ∼ 3048 at 150 Hz. Flexible piezoelectric PVDF-CNT foam based nanogenerator was fabricated, which generates high output voltage ∼12 V and current density of 30 nA/cm2 at small compressive pressure of 0.02 kgf. Piezoelectric output performance was measured under different humid condition and an output voltage up to 8 V was achieved even under 60% RH condition. PVDF-CNT foam exhibited hydrophobic behavior and high surface water contact angle of 139°. Such high output voltage even under small pressure, without applying electrical poling and under humid condition was originated though CNT induced self-alignment of electric dipoles in PVDF polymer. These excellent performances of developed foam based device confirmed its potential application in organic based ultrasensitive self-powered nanosensors and nanosystems.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 98%

Humidity Sustainable Hydrophobic Poly(vinylidene fluoride)-Carbon Nanotubes Foam Based Piezoelectric Nanogenerator

Badatya

Bharti

Sathish

et al. 2021

ACS Appl. Mater. Interfaces

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“…GDLs are composed of a gas diffusion substrate (GDS) and a microporous layer (MPL), which are the vital transport channels of water and gas. − The conventional MPLs are fabricated via mixing carbon powder and hydrophobic agents, which are not effective in preventing the dehydration of PEM at dry operation conditions. − Therefore, to improve the water retaining capacity, researchers have tried to optimize the MPL by introducing hydrophilic materials (e.g., TiO 2 , HfO 2 ) or hydrophilic coatings (PANI). − However, most of these materials both have high contact resistance, thus declining the cell performance, and suffer from water flooding in the high-current-density region due to the strong water absorption of hydrophilic materials, hindering the diffusion of the reaction gas.…”

Section: Introductionmentioning

confidence: 99%

Hierarchical Carbon Nanotube Hybrid Films Modified Gas Diffusion Layer for High-Performance Proton-Exchange Membrane Fuel Cells

Zhang,

Liu,

Song

et al. 2023

ACS Sustainable Chem. Eng.

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The functional gas diffusion layer (GDL), serving as a water−gas transfer control medium, significantly influences the performance of proton-exchange membrane fuel cells (PEMFCs). To improve simultaneously the water retention and gas transport rates, we present a straightforward and effective strategy to prepare carbon nanotube (CNT) hybrid films as functional interlayers in GDLs. With single-walled CNTs and multiwalled CNTs in the weight ratio of 1:1, the as-prepared GDL exhibits optimized electrochemical performance under all of the experimental cases. Especially, the current density is increased to 3.36 A cm −2 at 0.6 V under 26% relative humidity (RH) and 4.87 A cm −2 at 0.2 V under 100% RH. It is because the CNT hybrid films with hierarchical pore structures in GDLs are valid for enhancing both self-humidification and mass-transfer performance. The micropores with reasonable wettability serve as capillary vessels for absorbing water to promote the retention of moisture in the proton-exchange membrane, while the mesopores provide preferential transport pathways for reaction gas. Our results demonstrate that the CNTbased GDL may illuminate the potential application of PEMFCs.

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“…Carbon fiber paper (CFP), with the properties of high porosity, good electrical conductivity, excellent mechanical strength, outstanding corrosion resistance, etc. [1], has become the ideal material as a gas diffusion layer (GDL) of proton exchange membrane fuel cells (PEMFCs) and provides reactant and product permeability, transport of electrons, and heat and support of membrane electrode assembly (MEA) [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Carbon Fiber Papers Prepared by Wet-Laid Technique Using PVB/PF Composite Fibers as the Binders

2023

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Carbon fiber paper (CFP) is one of the most important units of gas diffusion layer (GDL) in proton exchange membrane fuel cells (PEMFCs). The binder used in the wet-laid technique has a significant effect on the properties of CFP. In this work, the polyvinyl butyral/phenol-formaldehyde resin (PVB/PF) composite fibers firstly prepared by a dry spinning method were applied for CFP fabrication to replace traditional binders during the papermaking process and remove the PF impregnation process. In the composite fibers with a mass ratio of 5:5, PF phase with a size of about 2~3 μm evenly distributed in PVB matrix. PVB and PF were miscible to some degree, which was beneficial for their binding effect during hot-press. These composite fibers can successfully bind carbon fibers (CFs) during the papermaking process, and their residual carbon efficiently welded the CFs after heat treatment. The content and length of composite fibers in the mat affected the binding structure among CFs, which influenced the properties of CFP, increased the composite fibers’ content and reduced their length, significantly improving the strength of CFP. Therefore, the application of this solid fiber binder could enhance the comprehensive properties of CFP by adjusting the fibers’ parameters in the mat and also make the fabrication of CFP more environmentally friendly and low-cost.

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Optimizing the hydrophobicity of GDL to improve the fuel cell performance

Abstract: The gas diffusion layer (GDL) is an important component in the proton exchange membrane fuel cell (PEMFC), and the main function of GDL is to transfer water and gas.

Cited by 27 publications

References 31 publications

Humidity Sustainable Hydrophobic Poly(vinylidene fluoride)-Carbon Nanotubes Foam Based Piezoelectric Nanogenerator

Humidity Sustainable Hydrophobic Poly(vinylidene fluoride)-Carbon Nanotubes Foam Based Piezoelectric Nanogenerator

Hierarchical Carbon Nanotube Hybrid Films Modified Gas Diffusion Layer for High-Performance Proton-Exchange Membrane Fuel Cells

Carbon Fiber Papers Prepared by Wet-Laid Technique Using PVB/PF Composite Fibers as the Binders

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