Improving the water management in anion-exchange membrane fuel cells <i>via</i> ultra-thin, directly deposited solid polymer electrolyte

Veh, Philipp; Britton, Benjamin; Holdcroft, Steven; Zengerle, Roland; Vierrath, Severin; Breitwieser, Matthias

doi:10.1039/c9ra09628k

Cited by 39 publications

(34 citation statements)

References 23 publications

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“…The spikes in the cell voltage are most likely due to periodic drying in the cell, as the average relative humidity remained constant at 73% for the duration of the experiment. We postulate that this could have been improved if the dew points were slightly adjusted to ensure that the cell was adequately humidified as explained by Hassan et al , 87 a thinner membrane was used to increase water back-diffusion from the anode to the cathode creating a more than desirable water gradient inside the fuel cell as supported by Veh et al , 88 and the cathode catalyst layer (CCL) was coated at a higher loading, making it thicker in order to better attract and retain more back-diffused water and in turn decreasing the overall cell resistance and providing adequate water for ORR and AEM hydration as explained by Gutru et al , 89 in their recent, comprehensive review on water management strategies in AEMFCs. The H 2 /air longevity data is some of the only data reported in the literature for precious-metal-free cathode catalysts in AEMFCs, as indicated by Table S4 .…”

Section: Resultsmentioning

confidence: 99%

Transition-Metal- and Nitrogen-Doped Carbide-Derived Carbon/Carbon Nanotube Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

et al. 2021

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Transition-metal- and nitrogen-codoped carbide-derived carbon/carbon nanotube composites (M-N-CDC/CNT) have been prepared, characterized, and used as cathode catalysts in anion-exchange membrane fuel cells (AEMFCs). As transition metals, cobalt, iron, and a combination of both have been investigated. Metal and nitrogen are doped through a simple high-temperature pyrolysis technique with 1,10-phenanthroline as the N precursor. The physicochemical characterization shows the success of metal and nitrogen doping as well as very similar morphologies and textural properties of all three composite materials. The initial assessment of the oxygen reduction reaction (ORR) activity, employing the rotating ring–disk electrode method, indicates that the M-N-CDC/CNT catalysts exhibit a very good electrocatalytic performance in alkaline media. We find that the formation of HO 2 – species in the ORR catalysts depends on the specific metal composition (Co, Fe, or CoFe). All three materials show excellent stability with a negligible decline in their performance after 10000 consecutive potential cycles. The very good performance of the M-N-CDC/CNT catalyst materials is attributed to the presence of M-N x and pyridinic-N moieties as well as both micro- and mesoporous structures. Finally, the catalysts exhibit excellent performance in in situ tests in H 2 /O 2 AEMFCs, with the CoFe-N-CDC/CNT reaching a current density close to 500 mA cm –2 at 0.75 V and a peak power density ( P max ) exceeding 1 W cm –2 . Additional tests show that P max reaches 0.8 W cm –2 in an H 2 /CO 2 -free air system and that the CoFe-N-CDC/CNT material exhibits good stability under both AEMFC operating conditions.

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Section: Resultsmentioning

confidence: 99%

Transition-Metal- and Nitrogen-Doped Carbide-Derived Carbon/Carbon Nanotube Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

et al. 2021

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“…As AEM is in between the water production zone (anode) and water consumption zone (cathode), it experiences a severe water imbalance. It is to be noted that water moves through the AEM in microns which greatly reduced the ionic resistance and improved the power density up to 1 W/cm 2 at 70 ℃, while the traditionally used of GDE and free standing AEM method delivered 0.4 W/cm 2 as represented in Figure 7 [144]. The better performance of thinner AEM was not only attributed to low Ohmic resistance but also to a better water distribution across the cell as thin AEM is able to permeate the large amount of water generated at anode to mitigate anode flooding and cathode dry out at high current densities [142,145].…”

Section: Aemmentioning

confidence: 98%

A comprehensive review on water management strategies and developments in anion exchange membrane fuel cells

Rambabu

Turtayeva

et al. 2020

International Journal of Hydrogen Energy

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In spite of significant achievements in alkaline exchange membrane fuel cells (AEMFCs) in recent years, they are still lagging behind proton exchange membrane fuel cells (PEMFCs) due to performance instability. Among the relevant operational parameters of AEMFC, the researchers have found that poor water management within the cell was the main reason for failure of the system. In the past five years, numerous modeling and experimental works were reported proposing different strategies to improve water management of AEMFC. The achievable power output in AEMFCs is then comparable with that of PEMFCs or even more. Efforts have to be continued, but AEMFCs can become a strong competitor in the market place. This review paper discusses the strategies and developments impacting water management of AEMFCs providing knowledge source for upcoming studies.

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“…As is well known, the ORR in the cathode consumes H 2 O, which easily leads to local drying‐out of the cathode, especially under high current densities and low cell potential. [ 41 ] Based on the above considerations, the operating conditions [ 37 ] (gas flow rate, cell temperature, and relative humidity) and GDE structure [ 42 ] (hydrophilicity, MPL, and GDL) must be optimized, which will be introduced in the following sections.…”

Section: Overall Mea For Aemfcmentioning

confidence: 99%

Recent Insights on Catalyst Layers for Anion Exchange Membrane Fuel Cells

et al. 2021

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Anion exchange membrane fuel cells (AEMFCs) performance have significantly improved in the last decade (>1 W cm−2), and is now comparable with that of proton exchange membrane fuel cells (PEMFCs). At high current densities, issues in the catalyst layer (CL, composed of catalyst and ionomer), like oxygen transfer, water balance, and microstructural evolution, play important roles in the performance. In addition, CLs for AEMFCs have different requirements than for PEMFCs, such as chemical/physical stability, reaction mechanism, and mass transfer, because of different conductive media and pH environment. The anion exchange ionomer (AEI), which is the soluble or dispersed analogue of the anion exchange membrane (AEM), is required for hydroxide transport in the CL and is normally handled separately with the electrocatalyst during the electrode fabrication process. The importance of the AEI–catalyst interface in maximizing the utilization of electrocatalyst and fuel/oxygen transfer process must be carefully investigated. This review briefly covers new concepts in the complex AEMFC catalyst layer, before a detailed discussion on advances in CLs based on the design of AEIs and electrocatalysts. The importance of the structure–function relationship is highlighted with the aim of directing the further development of CLs for high‐performance AEMFC.

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Improving the water management in anion-exchange membrane fuel cells via ultra-thin, directly deposited solid polymer electrolyte

Abstract: Thin ionomer membranes are considered key to achieve high performances in anion exchange membrane fuel cells, as well as high performance robustness towards changes in relative humidity.

Cited by 39 publications

References 23 publications

Transition-Metal- and Nitrogen-Doped Carbide-Derived Carbon/Carbon Nanotube Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

Transition-Metal- and Nitrogen-Doped Carbide-Derived Carbon/Carbon Nanotube Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

A comprehensive review on water management strategies and developments in anion exchange membrane fuel cells

Recent Insights on Catalyst Layers for Anion Exchange Membrane Fuel Cells

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