Modeling of Oxygen Diffusion Resistance in Polymer Electrolyte Fuel Cells in the Intermediate Potential Region

Suzuki, Takahisa; Yamada, Haruhiko; Tsusaka, Kyoko; Morimoto, Yu

doi:10.1149/2.0471803jes

Cited by 16 publications

(14 citation statements)

References 21 publications

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“…The limiting current is the maximum attainable current as the oxygen concentration on the surface of catalyst particles is depleted to zero, and it was used here to compare the mass transport ability of cathodes with various PTFE contents. [ 25 ] The total oxygen transport resistance is defined as the change of oxygen concentration divided by the average molar flux of oxygen, [ 23 ] and can be calculated from the cell limiting current based on Faraday's law and Fick's law

R_{normalT} = \frac{Δ C}{N_{{normalO}_{2}}}

N_{O_{2}} = ‐ D_{O_{2}}^{eff} \frac{{normald C}_{{normalO}_{2}}}{d δ}

N_{O_{2}} = \frac{normali}{4 F}

where Δ C is the change of oxygen concentration,

N_{O_{2}}

is the molar flux of oxygen, and

D_{O_{2}}^{eff}

is the effective diffusion coefficient of oxygen. F and δ represent the Faraday constant and oxygen transport length, respectively.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Interface Optimization toward Low Oxygen Transport Resistance in High‐Temperature Polymer Electrolyte Fuel Cells

Xiao

Xia

et al. 2020

Energy Tech

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Due to the enhanced tolerance of CO‐containing species under elevated operation temperature around 150–220 °C, high‐temperature polymer electrolyte fuel cells (HT‐PEFCs) have drawn extensive interest in the recent decades. One of the major challenges remaining for HT‐PEFCs is the inferior cell performance ascribed to poor catalytic activity and mass transport, which are mainly determined by the electrochemical interface structure involving phosphoric acid electrolyte. Herein, the electrochemical interfaces are investigated and optimized by adjusting the hydrophilic phases within the catalyst layer (CL) to modulate phosphoric acid redistribution in the cathode. The electrochemical surface area and interfacial oxygen transport resistance in the CL are optimized by balancing the coverage of polytetrafluoroethylene (PTFE) and phosphoric acid on the catalyst surface, thus achieving an enhanced cell performance of the HT‐PEFC of up to 328.12 mW cm−2. This balancing strategy for optimizing the electrochemical interfacial structure could shed light on the development of electrode architecture design for energy conversion and storage devices.

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R_{normalT} = \frac{Δ C}{N_{{normalO}_{2}}}

N_{O_{2}} = ‐ D_{O_{2}}^{eff} \frac{{normald C}_{{normalO}_{2}}}{d δ}

N_{O_{2}} = \frac{normali}{4 F}

where Δ C is the change of oxygen concentration,

N_{O_{2}}

is the molar flux of oxygen, and

D_{O_{2}}^{eff}

is the effective diffusion coefficient of oxygen. F and δ represent the Faraday constant and oxygen transport length, respectively.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Interface Optimization toward Low Oxygen Transport Resistance in High‐Temperature Polymer Electrolyte Fuel Cells

Xiao

Xia

et al. 2020

Energy Tech

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“…While the voltage of the Pt/C catalyst layer sharply attenuates in the high-current-density region, the CO ads Pt/C catalyst layer can maintain a certain power density even though the voltage decreases, especially at RH 20%. It is also found that with the reduction in RH, the proton conductivity and oxygen permeability of the ionomer decrease due to the decreased hydrophilic area at a lower water activity. ,, The sulfonic groups of the ionomer tend to bind more closely to the surface of Pt at lower humidity, worsening the oxygen transportation. ,− Therefore, the effect of ionomer distribution on oxygen transport resistance is more obvious at a lower RH.…”

Section: Resultsmentioning

confidence: 99%

Micromodification of the Catalyst Layer by CO to Increase Pt Utilization for Proton-Exchange Membrane Fuel Cells

Wen

Banham

et al. 2022

ACS Appl. Mater. Interfaces

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Improving the utilization of platinum in proton-exchange membrane (PEM) fuel cells is critical to reducing their cost. In the past decade, numerous Pt-based oxygen reduction reaction catalysts with high specific and mass activities have been developed. However, the high activities are mostly achieved in rotating disk electrode (RDE) measurement and have rarely been accomplished at the membrane electrode assembly (MEA) level. The failure of these direct translations from RDE to MEA has been well documented with several key reasons having been previously identified. One of them is the resistance caused by complex mass transport pathways in the MEA. Herein, we improve the proton and oxygen transportations in the MEA by building a thin and uniform distribution of ionomer on the catalyst surface. As a result, a PEM fuel cell design is capable of showing a current density improvement of 38% at the same voltage (0.6 V) under the H 2 /air operation.

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“…More importantly, the performance of Pt/C-[MTBD][C 4 F 9 SO 3 ] in the high current density region was greatly improved, which is believed to be associated with facilitated oxygen transport within the electrode. In general, the oxygen transport resistance in the electrode mainly consists of the molecular diffusion resistance in the pores and the transport resistance at the interface between the ionomer and Pt [38][39][40][41]. It is likely that IL reduced the oxygen transport resistance by homogenously distributing the ionomer in the electrode [42,43] or increasing the oxygen permeability at the interface of Pt and ionomer [40].…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the hydrophobic IL may limit the product water build up that hinders the mass transport of O 2 [10]. The experimental measurements of O 2 transport resistance using an internally established method [38,39] are ongoing to explore the mechanism. the mass transport of O2 [10].…”

Section: Resultsmentioning

confidence: 99%

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The Activity Enhancement Effect of Ionic Liquids on Oxygen Reduction Reaction Catalysts: From Rotating Disk Electrode to Membrane Electrode Assembly

Huang¹,

Morales‐Collazo

Chen

et al. 2021

Catalysts

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Ionic liquids (ILs) have been explored as a surface modification strategy to promote the oxygen reduction reaction (ORR) on Pt/C and their chemical structures were identified to have strong influence on the ORR activities. To better understand the roles of anion and cation of ILs on the catalytic reaction, two cations ([MTBD]+ and [bmim]+) were paired with three anions ([TFSI]−, [beti]−, and [C4F9SO3]−) to form various IL structures. By systematically varying the IL combinations and studying their effects on the electrochemical behaviors, such as electrochemical surface area and specific ORR activities, it was found that cation structure had a higher influence than anion, and the impact of the [MTBD]+ series was stronger than the [bmim]+ series. In addition to the investigation in the half-cell, studies were also extended to the membrane electrode assembly (MEA). Considerable performance enhancements were demonstrated in both the kinetic region and high current density region with the aid of IL. This work suggests that IL modification can provide a complementary approach to improve the performance of proton exchange membrane fuel cells.

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Modeling of Oxygen Diffusion Resistance in Polymer Electrolyte Fuel Cells in the Intermediate Potential Region

Cited by 16 publications

References 21 publications

Electrochemical Interface Optimization toward Low Oxygen Transport Resistance in High‐Temperature Polymer Electrolyte Fuel Cells

Electrochemical Interface Optimization toward Low Oxygen Transport Resistance in High‐Temperature Polymer Electrolyte Fuel Cells

Micromodification of the Catalyst Layer by CO to Increase Pt Utilization for Proton-Exchange Membrane Fuel Cells

The Activity Enhancement Effect of Ionic Liquids on Oxygen Reduction Reaction Catalysts: From Rotating Disk Electrode to Membrane Electrode Assembly

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