A Review of Molecular-Level Mechanism of Membrane Degradation in the Polymer Electrolyte Fuel Cell

Ishimoto, Takayoshi; Koyama, Michihisa

doi:10.3390/membranes2030395

Cited by 56 publications

(26 citation statements)

References 144 publications

(155 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Polymer electrolyte fuel cells (PEFCs) have been widely investigated as technologies for the transportation sector [1][2][3][4][5][6], portable power generation [5], and residential co-generation systems [1,3,4,6] because of their environmentally friendly operation [1,3,4,6], modularity [4], and high energy conversion efficiency [1,2,5,6]. However, some long-standing issues remain, including the high cost of platinum (Pt), unreliable performance, and poor durability, which are major impediments to largescale commercialization of the PEFC [1,2,4,5,[7][8][9][10]. Pt and Pt-based alloys are generally the most used catalysts for PEFC because Pt exhibits the highest catalytic activity for the oxygen reduction reaction (ORR), chemical stability, high exchange current density, and superior work function [10].…”

Section: Introductionmentioning

confidence: 99%

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

2019

Self Cite

View full text Add to dashboard Cite

While Pt-nanoparticles supported on SnO 2 exhibit improved durability, a substantial detriment is observed on the Ptnanoparticles' activity toward the oxygen reduction reaction. A density functional theory method is used to calculate isolated, SnO 2 -and graphene-supported Pt-nanoparticles. Work function difference between the Pt-nanoparticles and SnO 2 leads to electron donation from the nanoparticles to the support, making the outer-shell atoms of the supported nanoparticles more positively charged compared to unsupported nanoparticles. From an electrostatic point of view, nucleophilic species tend to interact more stably with less negatively charged Pt atoms blocking the active sites for the reaction to occur, which can explain the low activity of Pt-nanoparticles supported on SnO 2 . Introducing oxygen vacancies and Nb dopants on SnO 2 decreases the support work function, which not only reduces the charge transferred from the Pt-nanoparticles to the support but also reverses the direction of the electrons flow making the surface Pt atoms more negatively charged. A similar effect is observed when using graphene, which has a lower work function than Pt. Thus, the blocking of the active sites by nucleophilic species decreases, hence increasing the activity. These results provide a clue to improve the activity by modifying the support work function and by selecting a support material with an appropriate work function to control the charge of the nanoparticle's surface atoms. Graphic abstractKeywords Density functional theory · Platinum nanoparticles · SnO 2 · Support effect · Polymer electrolyte fuel cells Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s4245 2-019-1478-0) contains supplementary material, which is available to authorized users.* Michihisa Koyama, koyama.michihisa@nims.go.jp |

show abstract

Section: Introductionmentioning

confidence: 99%

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is also found that the identified two major degradation pathways from the side chain, i.e., ether bond cleavage at the deprotonated state and sulfo-unzipping pathway at the protonated state, can also be seen in the Nafion-like side chain [2,5]. far, counter measure for sulfo-unzipping pathway has been proposed [11].…”

Section: Polymer Degradation In Polymer Electrolyte Fuel Cellmentioning

confidence: 93%

“…The degradation of polymer electrolyte by OH radical in polymer electrolyte fuel cell (PEFC) is one of the crucial issues to be solved for higher durability of the cell [2][3][4][5][6]. While the unzipping mechanism from -COOH at the main chain terminal is well-known as degradation pathways of perfluorinated sulfonic acid (PFSA) polymer, another degradation pathway of polymer electrolyte was pointed out [7].…”

Section: Polymer Degradation In Polymer Electrolyte Fuel Cellmentioning

confidence: 99%

Applications of Computational Chemistry to Designing Materials and Microstructure in Fuel Cell Technologies

Koyama

Kohno

Ogura

et al. 2013

J. Comput. Chem. Jpn.

Self Cite

View full text Add to dashboard Cite

Our recent applications of computational chemistry methods to practical issues in fuel cell technologies are reviewed in the manuscript; i.e., degradation of polymer electrolyte and platinum catalyst in a polymer electrolyte fuel cell (PEFC), development of platinum alternative catalyst for low temperature fuel cells, sulfur poisoning and microstructure optimization of solid oxide fuel cell anode. As degradation issues in PEFC, degradation mechanisms of polymer electrolyte from side chain and platinum dissolution from catalyst surface are clarified by using a density functional method. A novel metal-organic framework as a potential platinum alternative catalyst is studied and the ethanol oxidation pathway over the catalyst is clarified. Then the importance of subsurface sulfur to understand the experimentallyobserved cell performance decrease by the sulfur impurity is pointed out. Finally, a microstructure-based index for designing microstructure with better overpotential characteristics is discussed on the basis of simulation data obtained for a number of different microstructures.

show abstract

“…These reactions result in shorting main chains and consequently in loss of the equivalent weight of the polymer. Other studies [21,48,49] have proved a degradation of the side chains corresponding to reactions (9)e (11). In this case, hydroxyl radicals attack CeO bonds in the ether groups of the side chains.…”

Section: Membrane Thickness and Conductivitymentioning

confidence: 98%

“…At the last decade, numerous degradation models have been published [19e43]. Most of the models consider degradation phenomena in a single component of the fuel cell: either in the membrane [21,25,28,29], or in the catalyst layer [20,23,24,26,27,30], or in the gas diffusion layer [22]. There are much less models predicting durability [19,34,35,40e44] or performance [25,33e39] of a complete fuel cell or stack.…”

Section: Introductionmentioning

confidence: 99%

Membrane degradation model for 3D CFD analysis of fuel cell performance as a function of time

Karpenko-Jereb

Sternig

Fink

et al. 2016

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

Available online xxxKeywords: Polymer electrolyte fuel cell Nafion degradation Modelling Computational fluid dynamics Local operating condition a b s t r a c t The paper describes a development of a degradation model, which enables to predict timedependent changes in performance of a polymer electrolyte fuel cell. The developed model consists of two main parts: 1) a new semi-empirical model taking into account changes in physico-chemical properties of a polymer electrolyte membrane operating in the fuel cell, 2) a validated CFD model computing the 3D performance of the cell. In the semi-empirical model, the degradation rates of the membrane thickness and conductivity depend on the oxygen crossover rate. The acid group concentration is calculated from the membrane conductivity based on the percolation theory approach. The gas diffusion coefficients are modelled empirically as a function of the membrane thickness. The model of the membrane degradation is coupled with the CFD model and applied to analyse the cell behaviour as a function of time. The simulation shows that the cell current density decreases faster with lowering relative humidity and increasing temperature. The in-plane degradation of the membrane is non-uniform and depends on the local operating condition.

show abstract

A Review of Molecular-Level Mechanism of Membrane Degradation in the Polymer Electrolyte Fuel Cell

Cited by 56 publications

References 144 publications

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

Applications of Computational Chemistry to Designing Materials and Microstructure in Fuel Cell Technologies

Membrane degradation model for 3D CFD analysis of fuel cell performance as a function of time

Contact Info

Product

Resources

About