Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics

Engebretsen, Erik; Hinds, Gareth; Meyer, Quentin; Mason, Tom; Brightman, Edward; Castanheira, Luis; Shearing, Paul R.; Brett, Dan J. L.

doi:10.1016/j.jpowsour.2018.02.022

Cited by 17 publications

(18 citation statements)

References 46 publications

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“…Although local hydration state of the membrane can be gauged using localised HFR measurements [52], it is not a direct indicator of the water distributuon in the channel. Neutron imaging on the other hand, provides detailed information on local liquid water accumulation, transport and distribution for the different serpentine flow-fields ( Fig.…”

Section: Neutron Imaging Of Water Distributionmentioning

confidence: 99%

Effect of serpentine flow-field design on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Cho

Neville

et al. 2018

Journal of Power Sources

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In-depth understanding of the dynamics of water formation, accumulation and removal is important for flow-field design optimization to ensure robust performance and durability of polymer electrolyte fuel cells (PEFCs). Here, in-operando neutron radiography is used to display and quantify liquid water distribution across the entire active area of single-, double-and quad-channel serpentine flow-fields. The results revealed that the water management and performance of PEFCs is strongly affected by the number of serpentine channels in the cathode flow-field. The single-channel serpentine-based PEFC exhibits both a better cell performance and uniformity in the local water distribution. The quad-channel based PEFC exhibits the largest voltage fluctuations caused by severe water flooding in the gas channels. However, the single-channel design leads to significantly larger pressure drop than the multiple-channel counterparts, which requires much higher parasitic power to pressurize and recirculate the reactants. Three different regimes of operation can be defined based on the current density: gradually increasing hydration (< 400 mA cm-2), flooding (400 mA cm-2 ≤ j ≤ 600 mA cm-2) and drying out (>600 mA cm-2). The reduced overall quantity of water in the channels with an increase in current density can be attributed to faster gas velocity and higher cell temperature.

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Section: Neutron Imaging Of Water Distributionmentioning

confidence: 99%

Effect of serpentine flow-field design on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Cho

Neville

et al. 2018

Journal of Power Sources

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“…Both approaches have been used to obtain information about the humidity condition of the cathode, anode and cathode starvation, voltage losses due to kinetic limitations and/or crossover of fuel . A point that was never addressed is what happens to the cathode when the fuel cell is operated in an oscillatory regime.…”

Section: Introductionmentioning

confidence: 99%

Coupled Dynamics of Anode and Cathode in Proton‐Exchange Membrane Fuel Cells

2019

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An external reference electrode was used to monitor individually the evolution of the anodic and cathodic potentials during the stationary as well as oscillatory operation of a Direct Formic Acid Fuel Cell (DFAFC) and a Direct Methanol Fuel Cell (DMFC). Besides evidencing the large activation loss in both cells, we were able to observe how the oscillatory operation of such devices affects their cathodes. In fact, cathodic oscillations synchronized with the cell voltage dynamics were observed, hitherto never reported on fuel cells. We have addressed these phenomena taking into account two main coupling processes: through the proton concentration and a global coupling stemming from the control mode (potentiostatic or galvanostatic).

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“…locations from the gas inlet to exhaust, highlighting mass-transport limitation and increase in ohmic resistance due to fuel starvation (Figure 8c,d). [90] Altogether, the identification and mitigation of uneven current densities distribution are invaluable toward improving the design and durability of PEMFCs. However, the current-density distribution cannot be dissociated from the heat distribution and water distribution, as these variables are deeply interconnected, as demonstrated further.…”

Section: Distribution Of Current Densitiesmentioning

confidence: 99%

In Situ and Operando Characterization of Proton Exchange Membrane Fuel Cells

2019

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For proton-exchange-membrane fuel cells (PEMFCs) to become a mainstream energy source, significant improvements in their performance, durability, and efficiency are necessary. To improve their durability, there must be a solid understanding of how the structural and electrochemical processes are affected during operation to propose mitigation strategies. To this aim, in situ and operando characterization techniques locally identify structural and electrochemical processes, which cannot be captured using conventional techniques. Nevertheless, linking these properties in the same geometric area has been challenging due to its inherent limitations, such as sample size and imaging resolution. This has created a knowledge gap in structure-to-electrochemical performance relationships as operation and degradation unevenly affect different areas of the cell.

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Localised electrochemical impedance measurements of a polymer electrolyte fuel cell using a reference electrode array to give cathode-specific measurements and examine membrane hydration dynamics

Cited by 17 publications

References 46 publications

Effect of serpentine flow-field design on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Effect of serpentine flow-field design on the water management of polymer electrolyte fuel cells: An in-operando neutron radiography study

Coupled Dynamics of Anode and Cathode in Proton‐Exchange Membrane Fuel Cells

In Situ and Operando Characterization of Proton Exchange Membrane Fuel Cells

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