Rapid and Flash Tests: Indicator for Quality of HT‐PEM Fuel Cells Batches?

Rastedt, Maren; Büsselmann, Julian; Tullius, Vietja; Wagner, Peter; Dyck, Alexander

doi:10.1002/fuce.201700177

Cited by 10 publications

(7 citation statements)

References 22 publications

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“…The voltage difference between 10 h and 60 h of constant load operation displays a decrease, or stagnation, by −3, −5 and 0 mV for standard MEAs 1–3 (Supporting Information Table S2). This evidences that MEA activation is completed after 60 h and slight voltage decreases occur due to the emergence of degradations, which is in accordance with our previous study of commercial HT‐PEM MEAs [32] . However, for the hybrid MEAs an increase of 12 mV for 0.40 mg Pt cm −2 and 15 mV for 0.65 mg Pt cm −2 loaded MEA can be seen over the same period.…”

Section: Resultssupporting

confidence: 91%

“…This evidences that MEA activation is completed after 60 h and slight voltage decreases occur due to the emergence of degradations, which is in accordance with our previous study of commercial HT-PEM MEAs. [32] However, for the hybrid MEAs an increase of 12 mV for 0.40 mg Pt cm À 2 and 15 mV for 0.65 mg Pt cm À 2 loaded MEA can be seen over the same period. This reveals that the activation process is still on-going after 60 h, which may be attributed to a slow phosphoric acid redistribution due to FeÀ NÀ C. Interestingly, the commonly observed voltage decay within the first hours of operation of FeÀ NÀ C-based HT-and LT-PEM MEAs [9,21,33] (Supporting Information Figure S1) is not observed for hybrid MEAs.…”

Section: First Activation Period and Performancementioning

confidence: 84%

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Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells – Effect of Fe−N−C in Pt‐Alloy Cathodes

et al. 2023

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Pt poisoning by phosphate in high temperature proton exchange membrane fuel cells (HT‐PEMFC) leads to loadings up to 1 mgPt cm−2 per electrode of costly materials. While cheaper Fe−N−C catalysts are unaffected by phosphate deactivation and contribute to the catalysis of the oxygen reduction reaction, their volumetric activity is substantially lower. In this study, the effect of Pt‐loading reduced hybrid cathodes for HT‐PEMFC is investigated using commercial Celtec®‐P‐based assembling. A promising effect of Fe−N−C incorporation in terms of acid attraction and activity retention is found. A longer activation (230 h, 0.3 A cm−2) for the hybrid membrane electrode assembly (MEA) is necessary, due to the slower acid distribution within Fe−N−Cs. This study shows the potential of Pt‐content reduction by up to 25 % compared to standard MEA using hybrid electrodes. Moreover, important insights for future strategies of cell activation are revealed for these hybrid MEAs.

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Section: Resultssupporting

confidence: 91%

Section: First Activation Period and Performancementioning

confidence: 84%

Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells – Effect of Fe−N−C in Pt‐Alloy Cathodes

et al. 2023

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“…The values for thicknesses were calculated by averaging ten values of five sagittal or coronal 2D-images [30]. The settings used for these investigations are summarized and shown in Table 1 [25].…”

Section: Experimental Setup 21 Hardware Setupmentioning

confidence: 99%

“…Those undesirable reactions could have an influence on changes inside the MEA, e.g. in thickness and / or on the morphology [25,26]. Therefore, to increase the lifetime of HT-PEM FCs the effects of H 2 starvation need to be investigated in more detail.…”

Section: Introductionmentioning

confidence: 99%

Characterization methodology for anode starvation in HT-PEM fuel cells

Yezerska

Dushina²,

Liu³

et al. 2019

International Journal of Hydrogen Energy

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Degradation caused by fuel starvation may be an important reason for limited fuel cell lifetimes. In this work, we present an analytical characterization of the high temperature polymer exchange membrane fuel cell (HT-PEM FC) behavior under cycled anode starvation and subsequent regeneration conditions to investigate the impact of degradation due to H 2 starvation. Two membrane electrode assemblies (MEAs) with an active area of 21 cm 2 were operated of up to 550 minutes, which included up to 14 starvation / regeneration cycles. Overall cell voltage as well as current density distribution (S ++ unit) were measured simultaneously each minute during FC operation. The cyclicity of experiments was used to check the long term durability of the HT-PEM FC. After FC operation, micro-computed tomography (μ-CT) was applied to evaluate the influence of starvation on anode and cathode catalyst layer thicknesses.During starvation, cell voltage and current density distribution over the active area of the MEA significantly differed from nominal conditions. A significant drop in cell voltage from 0.6 to 0.1 V occured after approx. 20 minutes for the first starvation step, and after 10 minutes for all subsequent starvation steps. By contrast, the voltage response is immediately stable at 0.6 V during every regeneration step.During each starvation, the local current density reached up to 0.3 A•point -1 at the area near the gas inlet (9 cm 2 ) while near the outlet it drops to 0.01 A•point -1 . The deviation from a balanced current density distribution occurred after 10 minutes for the first starvation step, and after ca. 2 minutes for the subsequent starvation steps.Hence, compared to the voltage drop, the deviation from a balanced current density distribution always starts earlier. This indicates that the local current density distribution is more sensitive to local changes in the MEA than overal cell voltage drop. This finding may help to prevent undesirable influences of the starvation process.The μ-CT images showed that H 2 starvation lead to thickness decrease of ca. 20-30 % in both anode and cathode catalyst layers compared to a fresh MEA. Despite of the 14 starvation steps and the thinning of the catalyst layers the MEA presents stable cell voltage during regeneration.

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“…For these reasons, the longevity of MEAs was investigated by means of long-term tests (duration: 1 year) under a constant load of 0.3 A/cm 2 within the framework of QUALIFIX. In addition, qualities of MEAs were reviewed by carrying out small series of evaluations under load cycling conditions at high current densities and start/stop and potential cycling conditions [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Analysis of HT-PEM MEAs’ Long-Term Stabilities

Büsselmann¹,

Rastedt²,

Klicpera

et al. 2020

Energies

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Despite the great advantages of high-temperature polymer electrolyte membrane (HT-PEM) fuel cells over the low-temperature (LT) PEM alternative, such as enhanced reaction kinetics and higher tolerance against impurities like CO due to the higher operation temperature, the achievement of high lifetimes still remains a challenge. In order to improve the durability of the fuel cell, extensive research has been carried out on alternatives for the individual components. For this reason, this paper conducted extended long-term tests with three three membrane electrode assemblies (MEAs) from one manufacturer under different operational scenarios. The MEAs differed mainly by the membranes used and showed significantly different behaviors. While the first MEA reached the end of life already after 2600 h, the second one could pass 9800 h almost without any problems. The third MEA proved resistant to adverse conditions. For all three MEAs, extensive electrochemical characterizations and μ-CT examinations for the analysis of long-term stability are shown.

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Rapid and Flash Tests: Indicator for Quality of HT‐PEM Fuel Cells Batches?

Cited by 10 publications

References 22 publications

Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells – Effect of Fe−N−C in Pt‐Alloy Cathodes

Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells – Effect of Fe−N−C in Pt‐Alloy Cathodes

Characterization methodology for anode starvation in HT-PEM fuel cells

Analysis of HT-PEM MEAs’ Long-Term Stabilities

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