High-performance alkaline fuel cells using crosslinked composite anion exchange membrane

Zhao, Yun; Yu, Hongmei; Yang, Donglei; Li, Jin; Shao, Zhigang; Yi, Baolian

doi:10.1016/j.jpowsour.2012.08.053

Cited by 80 publications

(53 citation statements)

References 28 publications

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“…The PPD of 737 mW cm −2 is among the highest reported (Table II). [2][3][4][5]15,16,35 Conclusions GDL wetproofing increases HEMFC hydration. This leads to a performance tradeoff: IR is lower when the electrolyte is hydrated, but too much hydration induces mass transport losses through flooding.…”

Section: Resultsmentioning

confidence: 99%

Manipulating Water in High-Performance Hydroxide Exchange Membrane Fuel Cells through Asymmetric Humidification and Wetproofing

Kaspar

Letterio

Wittkopf

et al. 2015

J. Electrochem. Soc.

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Hydroxide exchange membrane fuel cells (HEMFCs) are an emerging low-cost alternative to conventional proton exchange membrane fuel cells. In addition to producing water at the anode, HEMFCs consume water at the cathode, leading to distinctive water transport behavior. We report that gas diffusion layer (GDL) wetproofing strictly lowers cell performance, but that the penalty is much higher when the anode side is wetproofed compared to the cathode side. We attribute this penalty primarily to mass transport losses from anode flooding, suggesting that cathode humidification may be more beneficial than anode humidification for this device. GDLs with little or no wetproofing perform best, yielding a competitive peak power density of 737 mW cm −2 .

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Section: Resultsmentioning

confidence: 99%

Manipulating Water in High-Performance Hydroxide Exchange Membrane Fuel Cells through Asymmetric Humidification and Wetproofing

Kaspar

Letterio

Wittkopf

et al. 2015

J. Electrochem. Soc.

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“…18 Moreover, stabilized, doped, or grafted membrane materials are not amenable to serve as a soluble ionomer for use in the preparation of catalyst inks, and presently only two commercial products (FuMA-Tech FAA-3 and Tokuyama AS-4) are available for the purpose of forming catalyst layers for AEMFCs, which has greatly hindered the study and advancement of catalyst coated membranes for AEMFCs.…”

Section: -11mentioning

confidence: 99%

The Control and Effect of Pore Size Distribution in AEMFC Catalyst Layers

Britton

Holdcroft

2016

J. Electrochem. Soc.

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Catalyst ink for anion-exchange catalyst coated membranes based on FuMA-Tech FAA-3 membranes and ionomer typically requires high-boiling solvents. Here, we investigate the disproportionate effect of even small quantities of high-boiling solvent in the catalyst ink on the catalyst layer microstructure. High porosity in the mesoporous regime, 20-100 nm, is found to be an essential characteristic of effective anion-exchange catalyst layers for increasing membrane hydroxide ion conductivity and reducing mass-transport losses. High porosity in the nanoporous regime (<20 nm pore diameter) facilitates improvements in the kinetic region of polarization curves at the expense of mass-transport losses. New strategies are introduced to improve the control of distribution of pore sizes in the catalyst layer and to increase the mesoporosity. Beginning-of-life power densities for O 2 /H 2 anion exchange membrane fuel cells (AEMFCs), under zero backpressure, were accordingly increased from 276 to 428 mW · cm −2 , placing it among the highest AEMFC power densities reported in the literature under the conditions studied, representing a significant improvement over previously reported performances for FAA-3. The study highlights a need to develop anion-exchange solid polymer ionomers soluble in low-boiling solvents for preparing catalyst inks, and a more rigorous evaluation of porosimetry data and catalyst layer preparation methods for O 2 /H 2 polymer electrolyte fuel cells rely on the electrochemical oxygen reduction reaction (ORR) and the hydrogen oxidation reaction (HOR) (Fig. S1). In proton-exchange membrane fuel cells (PEMFC), the reactions occur a highly acidic environment and are facile on Pt electrocatalayst.1 An alkaline environment opens the possibility of using stable, high activity, non-noble catalysts, 1-3 but analogous hydroxide-exchange membrane fuel cells (AEMFC) are less welldeveloped and the hydroxide ion diffuses more slowly than protons. 4 Nonetheless, comparable membrane conductivities have been shown. 5 Moreover, compared to liquid-based alkaline fuel cells, AEMFCs may confer a higher power density, may have the capacity to function with impurities in the fuel, and have the potential to operate in CO 2 -containing air, 2 especially under high current load. 6 Additionally, as most AEMFCs are hydrocarbon in nature, they may display a lower fuel crossover compared to perfluorosulfonate-based ionomers.A barrier to the development of AEMFC technology concerns the hydroxide-conducting polymer; namely, its poor chemical stability and low ion conductivity under typical fuel cell conditions. The same issue applies even more to the ionomer in the catalyst layer, which experiences rapid variations in hydration-state. In a typical anionexchange ionomer, both the polymer backbone and functional groups are subject to hydroxide attack, e.g., via β-Hoffman elimination or direct nucleophilic displacement of the functional groups.7,8 Cleavage of the polymer backbone primarily affects the mechanical properties of the membrane,...

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“…Furthermore, the electrochemical performances of Pt/C in the presence of IM-based AEI (PES-EtIm/OH) and QA-based AEI (AS-4) were studied. AS-4 is a commercially available QA-based ionomer, and it performed well in the electrode of AEMFCs [28]. For the sake of comparison, Nafion ionomer is used as the baseline, because Nafion is commonly utilized for the RDE measurement not only in acidic but also in alkaline medium [29,30].…”

Section: Electrochemical Study Of the Influence Of Im-based Aei On Thmentioning

confidence: 99%

Preparation and characterization of imidazolium-functionalized poly (ether sulfone) as anion exchange membrane and ionomer for fuel cell application

Shao

Zhang

et al. 2013

International Journal of Hydrogen Energy

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High-performance alkaline fuel cells using crosslinked composite anion exchange membrane

Cited by 80 publications

References 28 publications

Manipulating Water in High-Performance Hydroxide Exchange Membrane Fuel Cells through Asymmetric Humidification and Wetproofing

Manipulating Water in High-Performance Hydroxide Exchange Membrane Fuel Cells through Asymmetric Humidification and Wetproofing

The Control and Effect of Pore Size Distribution in AEMFC Catalyst Layers

Preparation and characterization of imidazolium-functionalized poly (ether sulfone) as anion exchange membrane and ionomer for fuel cell application

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