Intermediate-Temperature Fuel Cells Research Articles

ChemInform Abstract: Compound of (NH4)2SnP4O13 with High Proton Conductivity in Both Dry and Humid Atmospheres as Electrolyte for Intermediate Temperature Fuel Cells.

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A cell voltage equation for an intermediate temperature proton exchange membrane fuel cell

A zero dimensional isothermal model equation for a single Intermediate Temperature Fuel Cell is developed and expressed as a semi-empirical relationship for cell potential as a function of current density. The model is applicable to fuel cells in which reactants and water product are in the gaseous or vapour phase. The model considers the influence of electrode kinetics using the Butler Volmer equation, over the complete voltage range, Ohmic potential losses and the effect of mass transport through electrolyte films covering catalyst layers on kinetics and thermodynamics. The model is used to simulate the variation in polarisation behaviour of a hydrogen fuel cell using a phosphoric acid doped PBI membrane. Performance predictions using published parameters for electrode kinetics, thermodynamics, conductivity and mass transport are compared with data from a laboratory fuel cell. Agreement between the model predictions and experimental data are good and indicate the relatively simple cell voltage model equation is suitable for estimating fuel cell voltage and power performance.

Study of CuFe-Ce0.9Gd0.1O2-δ as IT-SOFC Anode: Catalytic Activity, Thermal Expansion, Morphology, Electrical Conductivity and Chemical Compatibility

CuFe-Ce0.9Gd0.1O2- (CF-CG) has been prepared in order to explore its potential as anode material for Intermediate Temperature Fuel Cell (IT-SOFC) for direct oxidation of methane. In this work, the catalytic activity, the thermal expansion coefficient, the morphology, the electrical conductivity and the chemical compatibility of this anode material with YSZ, LSGM and CGO, common electrolytes used in SOFC, have been studied. Catalytic activity results reveal that the presence of Fe affects both the CH4 reactivity and the formation of carbon deposits. The sample shows metallic behavior having an electrical conductivity value of 7.8 S cm-1 at 750°C under reducing atmosphere. The thermal expansion coefficients in both reducing and oxidizing atmosphere are matched to that of SOFC electrolytes. Reactivity studies have demonstrated an excellent chemical compatibility between this material and common SOFC electrolytes.

Fabrication of Protic Ionic Liquid/Sulfonated Polyimide Composite Membranes for Non-humidified Intermediate Temperature Fuel Cells

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Physicochemical Properties of Protic Ionic Liquids as Electrolyte for Non-humidified Intermediate Temperature Fuel Cell

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A high performance intermediate temperature fuel cell based on a thick oxide–carbonate electrolyte

A high performance intermediate temperature fuel cell (ITFC) with composite electrolyte composed of co-doped ceria Ce 0.8Gd 0.05Y 0.15O 1.9 (GYDC) and a binary carbonate-based (52 mol% Li 2CO 3/48 mol% Na 2CO 3), 1.2 mm thick electrolyte layer has been developed. Co-doped Ce 0.8Gd 0.05Y 0.15O 1.9 was synthesized by a glycine–nitrate process and used as solid support matrix for the composite electrolyte. The conductivity of both composite electrolyte and GYDC supporting substrate were measured by AC impedance spectroscopy. It showed a sharp conductivity jump at about 500 °C when the carbonates melted. Single cells with thick electrolyte layer were fabricated by a dry-pressing technique using NiO as anode and Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3− δ or lithiated NiO as cathode. The cell was tested at 450–550 °C using hydrogen as the fuel and air as the oxidant. Excellent performance with high power density of 670 mW cm −2 at 550 °C was achieved for a 1.2 mm thick composite electrolyte containing 40 wt% carbonates which is much higher than that of a cell based on pure GYDC with a 70 μm thick electrolyte layer.

Hydrophobic Protic Ionic Liquid for Nonhumidified Intermediate-temperature Fuel Cells

Abstract A novel protic ionic liquid ethylmethylpropylammonium nonafluorobutanesulfonate ([empa][NfO]) was found to exhibit hydrophobicity, high ionic conductivity, and facile electroactivity toward hydrogen oxidation and oxygen reduction reactions; these properties make it a suitable electrolyte for nonhumidified intermediate-temperature fuel cells.

Study of Dehydrated Salts: Electrolyte for Intermediate Temperature Fuel Cell

Fuel cells are receiving growing interest in recent years since they represent one of the most promising energy source to reduce pollutant emission. We propose some new dehydrated salts as an electrolyte in the intermediate temperature fuel cell. The proton conduction in the dehydrated salts was established by the study of DTA/TGA, infrared spectroscopic study, transference number, bulk electrical conductivity measurement and emf study. The electrical conductivity of the dehydrated salts becomes ionic and increases 100-1000 times in the hydrogen ambient with respect to vacuum.

An Oxide Ion and Proton Co-Ion Conducting Sn0.9In0.1P2O7 Electrolyte for Intermediate-Temperature Fuel Cells

The ionic conductivity of ceramic was investigated under various atmospheres within the temperature range of . Similar to mixed-conductive perovskite oxides at high temperatures (such as at ), can conduct both protons and oxide ions at low temperatures . The conductivity of reaches at in wet nitrogen. Its transport numbers determined by steam concentration cells are around 0.76 for a proton and 0.12 for an oxide ion. The performance of direct methanol fuel cells at using mixed-ion conductive electrolyte is higher than that at using pure proton conductive electrolyte. This is attributed to direct oxidation of CO at the anode by the oxide ions generated at the cathode and moved through the electrolyte.

Direct Alcohol Electro-oxidation in an Intermediate Temperature Fuel Cell

Anodic reactions in a direct alcohol fuel cell (DAFC) at intermediate temperature (250 oC) were investigated from the standpoint of achieving high performance. In order to evaluate the temperature effect on the electro-oxidation of small alcohols in the intermediate temperature region, a kinetic study on the electro-oxidation of methanol and ethanol on Pt/C was conducted using a single cell fabricated with CsH2PO4 proton conducting solid electrolyte. At 250 oC, the current density of ethanol electro-oxidation is comparable to that of methanol electro-oxidation in a low potential region (< 400 mV vs. RHE). In addition, the analysis of reaction products suggests that C-C bond cleavage in ethanol electro-oxidation can proceed at the intermediate temperature. Through the electrochemical measurements, characteristic features in the alcohol electro-oxidation at the intermediate temperature were discussed.

Direct Alcohol Electro-oxidation in an Intermediate Temperature Fuel Cell

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Fabrication of Protic Ionic Liquid/Sulfonated Polyimide Composite Membranes for Non-humidified Intermediate Temperature Fuel Cells

not Available.

Protic Ionic Liquid as an Electrolyte for Non-humidified Intermediate Temperature Fuel Cells

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Characterization of Au/ZrO2 Oxygen Reduction Reaction (ORR) Electrocatalyst for Intermediate-temperature Fuel Cells

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An Oxide Ion and Proton Co-Ion Conducting Sn0.9In0.1P2O7 Electrolyte for Intermediate-Temperature Fuel Cells

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Preparation of Solid Proton Conducting Y-Doped BaZrO3 Thin Film for Intermediate Temperature Fuel Cell

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A Proton Conducting Electrolyte Based on Imidazole Supported Inorganic Porous Matrix for the Unhumidified Intermediate Temperature Fuel Cell

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A Proton Conducting Electrolyte Based on Imidazole Supported Inorganic Porous Matrix for the Unhumidified Intermediate Temperature Fuel Cell

A proton conducting electrolyte based on imidazole supported inorganic porous matrix was examined to obtain the proton conductor that can operate without humidification at intermediate temperature. The proton conductivity of composite electrolytes with large pore size(0.1μm, 10μm) showed high at higher temperature than 363K, and dropped at lower temperature than 363K as well as imidazole(bulk). However the proton conductivity of composite electrolytes with small pore size(4nm) did not drop even at lower than 363K, that is, showed good temperature dependency. In addition coupling acid functional groups on the pore surfaces contribute to the raise of proton conductivity. These results suggest that high proton conductivity at wide range of temperature without humidification could be achieved by controlling pore size and the acid functional groups coupled with the pore surfaces.

Performance of fuel cells with proton-conducting ceria-based composite electrolyte and nickel-based electrodes

A ceria-based composite electrolyte with the composition of Ce 0.8Sm 0.2O 1.9 (SDC)–30 wt.% (2Li 2CO 3:1Na 2CO 3) is developed for intermediate temperature fuel cells (ITFCs). Two kinds of SDC powders are used to prepare the composite electrolytes, which are synthesized by oxalate coprecipitation process and glycine–nitrate process, respectively, and denoted as SDC(OCP) and SDC(GNP). Based on each composite electrolyte, two single cells with the electrolyte thickness of 0.3 and 0.5 mm are fabricated by dry-pressing technique, using nickel oxide as anode and lithiated nickel oxide as cathode, respectively. With H 2 as fuel and air as oxidant, all the four cells exhibit excellent performances at 400–600 °C, which can be attributed to the highly ionic conducting electrolyte and the compatible electrodes. The cell performance is influenced by the SDC morphology and the electrolyte thickness. More interestingly, such composite electrolytes are found to be proton conductors at intermediate temperature range for the first time since almost all water is observed at the cathode side during fuel cell operation for all cases. The unusual transport property, excellent cell performance and potential low cost make this kind of composite material a good candidate electrolyte for future cost-effective ITFCs.

Characterisation of La0.6Sr0.4Co0.2Fe0.8O3-d and Ba0.5Sr0.5Co0.8Fe0.2O3-d as Cathode Materials for the Application in Intermediate Temperature Fuel Cells

Capable materials for solid oxide fuel cell cathodes have to provide high electrocatalytic activity for oxygen reduction as well as sufficient electronic conductivity and good ionic transport properties. This study compares the electrical transport properties and the oxygen exchange properties of two promising cathode materials for operating temperatures between 600 and 800 {degree sign}C: La0.6Sr0.4Co0.2Fe0.8O3-d and Ba0.5Sr0.5Co0.8Fe0.2O3-d. Both materials were synthesized by spray pyrolysis and characterised with respect to phase purity and to the element ratio by XRD and ICP-AES analysis. The sintering behaviour of the calcined powders and the coefficients of thermal expansion of dense sintered samples were studied by dilatometry. As important parameters for the oxygen exchange reaction the chemical surface exchange coefficients and chemical diffusion coefficients as well as the electrical conductivities are compared.