Neutron Imaging for the Hydrogen Economy

Arif, Muhammad; Hussey, Daniel S.; Jacobson, David L.

doi:10.1007/978-0-387-78693-3_11

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…Neutron Imaging is a powerful technique in developing greater understanding of water distribution profiles during PEFC operation. 18,20,21 Particularly, it has the ability to simultaneously correlate water distribution across the MEA under realistic cell operating conditions with spatial resolutions of ≈ 25 μm. This experiment provides data to calculate the amount of water across the MEA of an operating PEFC (Fig.…”

Section: Resultsmentioning

confidence: 99%

Diagnosing the Effects of Ammonia Exposure on PEFC Cathodes

Lopes

Sansiñena

Hussey

et al. 2014

J. Electrochem. Soc.

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The performance degradation and recovery of a polymer electrolyte fuel cell exposed to ammonia is described. The effect of ammonia contamination on each component of the MEA was studied using Neutron Imaging, lifetime tests, cell polarization measurements, potentiostatic measurements, and AC impedance spectroscopy. It is found that among the detrimental effects of the contaminant, mass transport and ORR kinectic are mostly affected. Reductions in electrolyte conductivity are not playing a major role in cell performance losses for the low levels of contamination studied here. Shifts in electrolyte proton activity reduce oxygen reduction reaction mixed equilibrium potential and so cell potential. In addition, cell potential might also be affected by overpotentials on the oxygen reduction reaction caused by oxidation of ammonia at cell potential above 0.7 V. It is demonstrated that cell initial performance can be recovered after contamination and ammonia-contaminated PEFC recovering mechanisms are discussed.

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Section: Resultsmentioning

confidence: 99%

Diagnosing the Effects of Ammonia Exposure on PEFC Cathodes

Lopes

Sansiñena

Hussey

et al. 2014

J. Electrochem. Soc.

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“…The application of NRAD, as the only suitable analytical method for the in situ visualization of the water here, and its management within fuel cells (FCs) to optimize their performance, is well understood; it has been widely demonstrated by various scientific groups/authors. − However, limited research has been conducted on the utilization of NRAD as an analytical technique in the optimization of electrolyzers. Selamet et al found that oxygen evolution occurs in the anode section and flooding results in the cathode due to water crossover, when using the in-plane configuration.…”

Section: Experimental Section: Instrumentation and Methodologymentioning

confidence: 99%

Current Density Distribution of Electrolyzer Flow Fields: In Situ Current Mapping and Neutron Radiography

2019

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A polymer electrolyte membrane water electrolyzer plays an important role in the development of renewable energy storage systems due to its high current density capability and quick response to intermittent input power variations. Mass transport limitation and temperature hot-spot formation within this type of electrolyzer cell will, however, lead to membrane degradation and lower efficiency. Robustness is highly dependent on the flow field (FF) design used because the FFs at the anode side serve the purpose of carrying the water, which acts as both a coolant and a reactant. In this study, two electrolyzer FF designs, both with an active area of 25 cm2, were fabricated in house at HySA Infrastructure (South Africa). Thereafter, they were characterized in terms of current density distribution and temperature distribution, using a segmented sensor plate (S++ Simulation Services, Germany) and quasidynamic neutron radiography. The water and gas content at both the anode and cathode sides were quantified at the Neutron Imaging Facility of the Center for Neutron Research, National Institute of Standards and Technology. It was found that a PIN-type FF design has a more homogeneous current and temperature density distribution across the surface of the FF than the parallel FF design.

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“…Some of these techniques include using novel magnetic resonance imaging methods [9], using hydrogen-deuterium to enhance contrast in nuclear magnetic resonance imaging [10], and refined neutron radiography techniques to yield high-resolution images [11][12][13][14]. Current literature contains many examples of 2D radiography images of the flow field, however, very few clear 3D tomography standards have been set [15][16][17]. Researchers at the National Institute of Standards and Technology (NIST) Neutron Imaging Facility (NNIF) have acquired the first in situ tomographic 3D images of an operating PEMFC demonstrating the power higher quality 3D images may afford those designing a cell's water management system [18,19].…”

Section: Introductionmentioning

confidence: 98%