Investigation on degradation mechanism of hydrogen–oxygen proton exchange membrane fuel cell under current cyclic loading

Meng, Kai; Chen, Ben; Zhou, Heng; Shen, Jun; Shen, Zu-Guo; Tu, Zhengkai

doi:10.1016/j.energy.2021.123045

Cited by 42 publications

(7 citation statements)

References 44 publications

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“…CV is a very useful research method for determining the electrochemically active area of a catalyst . CV measurements for the cathode were taken, as shown in Figure c,d.…”

Section: Resultsmentioning

confidence: 99%

“…Dead-ended anodes (DEAs) and cathodes are commonly used in hydrogen–oxygen fuel cells to increase the gas utilization rate. In H 2 /O 2 PEMFCs, water management is a difficulty. − The water generated in the cathode catalyst layer (CL) will diffuse back to the anode and accumulate, − causing local fuel starvation and catalyst carbon corrosion. − Yang et al optimized the flow channel structure and operation modes in the DEA configuration. According to Soopee et al, the internal water flooding of the flow channel in a fuel cell will become serious as the current density increases, which is consistent with the researches of Shao et al…”

Section: Introductionmentioning

confidence: 99%

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Catalyst Degradation Mitigation and Fuel Utilization Enhancement of a Dead-Ended Anode and Cathode Proton Exchange Membrane Fuel Cell with Periodical Oxygen Supply

Liu

Chan

2022

ACS Sustainable Chem. Eng.

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Hydrogen−oxygen proton exchange membrane fuel cells (PEMFCs) have promising military applications. However, carbon corrosion in the catalyst layer induced by water flooding significantly affects the performance and longevity of PEMFCs. In this study, a periodical oxygen supply strategy is proposed to improve water management in PEMFCs. The hydrogen and oxygen utilization reached 99.84 and 98.82%, respectively. The performance degradation rate of a PEMFC with a current density of 600 mA•cm −2 decreased by 45.1% under the proposed strategy. According to morphological results, the thickness degradation rate of the cathode catalyst layer operating in the proposed strategy is generally lower than that in the conventional dead-ended mode, which was mainly due to the irreversible Pt agglomeration, oxidation, and carbon support corrosion, especially in the oxygen outlet area. This work contributes to the engineering application of H 2 /O 2 PEMFCs by providing a deeper understanding of dead-ended behaviors.

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“…CV is a very useful research method for determining the electrochemically active area of a catalyst . CV measurements for the cathode were taken, as shown in Figure c,d.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catalyst Degradation Mitigation and Fuel Utilization Enhancement of a Dead-Ended Anode and Cathode Proton Exchange Membrane Fuel Cell with Periodical Oxygen Supply

Liu

Chan

2022

ACS Sustainable Chem. Eng.

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“…The Nafion consists of a fluorocarbon main chain and a side chain with an −SO 3 − group at the end. 41 Degradation of the ionomer is known to affect the MEA performance adversely 42 due to decreased proton conductivity and degradation of the catalyst/ ionomer interface, leading to inactive catalyst nanoparticles, and so forth. Here, the physical as well as chemical states of the ionomer phase have been explored through a combination of characterizations including microscopic and spectroscopic techniques.…”

Section: Variation Of S Content (Xrf and Elemental Analyses) As The P...mentioning

confidence: 99%

Insights into Degradation of the Membrane–Electrode Assembly Performance in Low-Temperature PEMFC: the Catalyst, the Ionomer, or the Interface?

Sharma

Morgen

Chiriaev

et al. 2022

ACS Appl. Mater. Interfaces

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Here, we report a study on the structural characteristics of membrane electrode assembly (MEA) samples obtained from a low-temperature (LT) polymer electrolyte membrane (PEM) fuel cell (FC) stack subjected to long-term durability testing for ∼18,500 h of nominal operation along with ∼900 on/off cycles accumulated over the operation time, with the total power production being 3.39 kW h/cm2 of MEA and the overall degradation being 87% based on performance loss. The chemical and physical states of the degraded MEAs were investigated through structural characterizations aiming to probe their different components, namely the cathode and anode electrocatalysts, the Nafion ionomer in the catalyst layers (CLs), the gas diffusion layers (GDLs), and the PEM. Surprisingly, X-ray diffraction and electron microscopy studies suggested no significant degradation of the electrocatalysts. Similarly, the cathode and anode GDLs exhibited no significant change in porosity and structure as indicated by BET analysis and helium ion microscopy. Nevertheless, X-ray fluorescence spectroscopy, elemental analysis through a CHNS analyzer, and comprehensive investigations by X-ray photoelectron spectroscopy suggested significant degradation of the Nafion, especially in terms of sulfur content, that is, the abundance of the −SO3 – groups responsible for H+ conduction. Hence, the degradation of the Nafion, in both of the CLs and in the PEM, was found to be the principal mechanism for performance degradation, while the Pt/C catalyst degradation in terms of particle size enlargement or mass loss was minimal. The study suggests that under real-life operating conditions, ionomer degradation plays a more significant role than electrocatalyst degradation in LT-PEMFCs, in contrast to many scientific studies under artificial stress conditions. Mitigation of the ionomer degradation must be emphasized as a strategy to improve the PEMFC’s durability.

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“…It should be noted that thinner membranes tend to increase the hydrogen permeability and reduce its mechanical performance, resulting in hydrogen-oxygen crossover and cracking of the membrane. 40 Therefore, the hydrogen permeability and mechanical performance need to be considered when choosing a thinner membrane. Figure 13B that the average temperature in the membrane increases with the decrease of membrane thickness, and the temperature difference is more apparent at high voltages.…”

Section: Effect Of Contact Angle and Porosity Of A-gdlmentioning

confidence: 99%

3D two‐phase and non‐isothermal modeling for PEM water electrolyzer: Heat and mass transfer characteristic investigation

Zhou

Meng

Chen

et al. 2022

Intl J of Energy Research

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A three-dimensional, two-phase, non-isothermal proton exchange membrane (PEM) water electrolyzer model was developed, aiming to reveal water and heat distribution characteristics and to explore the effects of various parameters on heat and mass transfer and performance of the electrolyzer. The results show that the electrolyzer performance depends on the combined effect of heat and mass, especially at high voltages. Although increasing the inlet velocity can accelerate the discharge of bubbles, it causes a larger temperature drop which degrades the performance. Increasing the inlet temperature can effectively improve the kinetic reaction rate of the catalyst layer and reduce the ohmic resistance of the membrane, which promotes the performance improvement. Decreasing the contact angle of anode gas diffusion layer (A-GDL) and increasing its porosity is beneficial to the transport of liquid water and improves the performance, but excessive porosity leads to a rapid increase in the ohmic resistance of A-GDL, and the optimal porosity range is 0.5 to 0.6. In addition, changes in A-GDL porosity and contact angle have little effect on temperature. Decreasing the thickness of the membrane can significantly improve the performance, but accelerate the increase of the membrane temperature at high voltage.

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Investigation on degradation mechanism of hydrogen–oxygen proton exchange membrane fuel cell under current cyclic loading

Cited by 42 publications

References 44 publications

Catalyst Degradation Mitigation and Fuel Utilization Enhancement of a Dead-Ended Anode and Cathode Proton Exchange Membrane Fuel Cell with Periodical Oxygen Supply

Catalyst Degradation Mitigation and Fuel Utilization Enhancement of a Dead-Ended Anode and Cathode Proton Exchange Membrane Fuel Cell with Periodical Oxygen Supply

Insights into Degradation of the Membrane–Electrode Assembly Performance in Low-Temperature PEMFC: the Catalyst, the Ionomer, or the Interface?

3D two‐phase and non‐isothermal modeling for PEM water electrolyzer: Heat and mass transfer characteristic investigation

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