SPEEK/functionalized silica composite membranes for polymer electrolyte fuel cells

Sambandam, Satheesh; Ramani, Vijay

doi:10.1016/j.jpowsour.2007.04.026

Cited by 136 publications

(72 citation statements)

References 62 publications

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“…7,17 Sambandam and Ramani 7 calculated Tafel slopes for SPEEK-based electrodes in the range of 70-83 mV/decade whereas our SS-CCE electrodes were found to have Tafel slopes of −2 ) combined with SPEEK membranes were lower than when SPEEKbased electrodes were used. The SPEEK-based electrodes had much lower membrane ohmic overpotential values than our SS-CCE electrodes, though the remaining overpotential values were similar in magnitude.…”

Section: Mea Characteristics-mentioning

confidence: 74%

“…The CCE fabrication method via in-situ polymerization is theorized to provide enhanced distribution of ionomer, in this case a mixture of sulfonated and unsulfonated silane precursors, through the catalyst layer. In this publication, the transport capabilities of MEAs prepared with a Nafion-based cathode catalyst layer and a CCE-based cathode catalyst layer have been examined and quantified using the methods by Williams et al 3 and Sambandam et al 2,7 Comparison of the polarization data and performance characteristics is presented. …”

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confidence: 99%

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Investigation of Transport Mechanisms for Sulfonated Silica-Based Fuel Cell Electrode Structures

Eastcott

Easton

2015

J. Electrochem. Soc.

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Ceramic carbon electrodes (CCEs) have demonstrated their ability to function as proton exchange membrane fuel cell electrodes under low relative humidity (RH) conditions. Small quantities of sulfonated silane in the catalyst layer produced electrodes with high surface area, porosity, and water retention which improved catalytic activity and proton conductivity. The purpose of this work was to investigate the mechanisms that facilitate enhanced performance of CCE electrodes under different RH conditions. Differences in transport phenomena related to membrane, electrode, and reactant concentration components were measured and compared for standard Nafion-based and CCE cathode catalyst layers using oxygen, air, helox (21% O 2 in He), and 4% O 2 in N 2 . Membrane electrode assemblies were characterized via cyclic voltammetry and electrochemical impedance spectroscopy. CCE cathodes displayed decreased resistance related protonic and electronic transport when relative humidity was lowered, and both types of electrodes suffered limitations due to oxygen transport losses where the oxygen also undergoes reduction in the catalyst layer. Remarkably, at 20% RH there was no change in performance at lower oxygen concentrations or mass transport loss observed for the CCE cathodes, indicating that the overall oxygen transport (through the gas diffusion layer and ionomer) is enhanced using this type of electrode structure. The performance output of an individual proton exchange membrane fuel cell (PEMFC), or a fuel cell stack, is dependent on many internal and external factors. Temperature, relative humidity, gas composition and flow, flow field design, and distribution of materials in the catalyst layer can all have a profound effect on the power output of a given membrane electrode assembly (MEA).1,2 Operation conditions are dynamic and changes to these conditions can manifest in the performance profile. Some of the most useful information can come from examination of polarization (I-V) curves as they are collected in the operating fuel cell environment; that is, when oxidant is present. It is essential to monitor performance losses and identify their sources in order to design and evaluate a viable catalyst layer. With the knowledge that gas transport is restricted, or that catalytic sites are unavailable, comes the ability to modify the catalyst layer or reaction conditions to mitigate loss and maintain reliable performance.There are a number of intrinsic losses associated with general fuel cell operation. The most basic of these losses are activation polarization losses, which are due to slow reaction kinetics at the electrodes as the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) will never reach theoretical efficiencies.1,3 The more efficient these reactions are (i.e., the greater the exchange current density), the lower the activation losses will be. Ohmic (or resistive) losses result from the ability of the ionomer material to transport protons through the membrane and catalyst layers, as well as ...

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Section: Mea Characteristics-mentioning

confidence: 74%

mentioning

confidence: 99%

Investigation of Transport Mechanisms for Sulfonated Silica-Based Fuel Cell Electrode Structures

Eastcott

Easton

2015

J. Electrochem. Soc.

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“…Lin et al, 2007;Sambandam & Ramani, 2007 ;Su et al, 2007;Tung & Hwang, 2007). Sol-gel derived sulfonated diphenyldimethoxysilane (SDDS) with hydrophilic -SO 3 H functional groups were used as the additive to reduce the methanol permeability of Nafion ® .…”

Section: Organic/silica Nanocomposite Membranesmentioning

confidence: 99%

“…Sulfonated poly(ether ether ketone) composite with sulfonic acid functionalized silica were prepared by casting (Sambandam & Ramani, 2007 ). At 80°C and 75% RH (relative humidity) the measured conductivity was 0.05 S cm -1 for SPEEK containing 10% sulfonic acid functionalized silica and 0.02 S cm -1 for the plain SPEEK membrane.…”

Section: Organic/silica Nanocomposite Membranesmentioning

confidence: 99%

Organic/Inorganic Nanocomposite Membranes Development for Low Temperature Fuel Cell Applications

Mokrani¹

2012

Advances in Chemical Engineering

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“…Proton conductivity of this membrane is mainly dependent on sulfonation *Address correspondence to this author at the School of Chemical Engineering, Huaihai Institute of Technology, Lianyungang Jiangsu 222005, China; E-mail: yangtao_hit@163.com degree (DS) [19][20]. The DS of SPEEK can be adjusted by sulfonation time, temperature and concentration of sulfuric acid conveniently [21][22][23][24]. However, the introduction of -SO 3 groups can destroy the ordered structure of SPEEK molecular and promote the decomposition of SPEEK [18].…”

Section: Introductionmentioning

confidence: 99%

Multilayer Membranes Based on Sulfonated Poly(Ether Ether Ketone) and Poly(Vinyl Alcohol) for Direct Methanol Membrane Fuel Cells

Yang¹,

Zhang²,

Gao³

et al. 2009

TOFCJ

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Much work has been conducted on the substitutes for Nafion as proton exchange membrane materials. Some researches are focused on the heterogeneous multilayered membranes reported by R. Jiang [J. Electrochem. Soc. 153 (2006) (2005) 59]. However, just as the dependence of methanol crossover upon the layer with the lowest permeability, the proton transfer ability is major confined by the layer with the poorest conductivity. Moreover, various swelling ratio and contractibility of sub-layers will make the hidden problems of separation between catalyst layer and proton exchange membrane become more obvious. We present here a multilayered membranes containing five thin layers of sulfonated poly(ether ether ketone)(SPEEK) and five thin layers of poly(vinyl alcohol)(PVA). SPEEK layers and PVA layers were located alternatively in the composite membrane. The swelling behaviors of PVA layer are restrained by both sideward SPEEK layers. Methanol crossover is efficiently alleviated piece by piece without visible proton conductivity loss. The preliminary investigation in DMFC suggests its promising application as resisting methanol and proton exchange membrane.

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SPEEK/functionalized silica composite membranes for polymer electrolyte fuel cells

Cited by 136 publications

References 62 publications

Investigation of Transport Mechanisms for Sulfonated Silica-Based Fuel Cell Electrode Structures

Investigation of Transport Mechanisms for Sulfonated Silica-Based Fuel Cell Electrode Structures

Organic/Inorganic Nanocomposite Membranes Development for Low Temperature Fuel Cell Applications

Multilayer Membranes Based on Sulfonated Poly(Ether Ether Ketone) and Poly(Vinyl Alcohol) for Direct Methanol Membrane Fuel Cells

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