Publications de Jan Van Herle | EPFL Graph Search

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A model for planar solid oxide fuel cell repeat elements and stacks has been developed. Distribution of concentrations, reaction rates and temperatures (both gases and solids) are computed as well as overall performance results. Specific experiments provide inputs to the model by a parameter estimation method. The modeling approach developed allows to compare several configurations. As the number of design parameters is large (from cell size, component thicknesses to gas flow configuration), the model is de

Results on solid oxide fuel cell stacks tested at 800° C with H2 fuel and using planar Ni-zirconia anode supported cells, 80x80x0.2 mm in size, are presented. Modeling and numerical simulation is used to interpret observed results and develop improved desi ...

Lifetime and durability issues connected with Solid Oxide Fuel Cell (SOFC) technology are strongly related to the amount of contaminants that reach the stack. In this study the focus is on organic silicon compounds (siloxanes) and their highly detrimental ...

Environmental transmission electron microscopy is used in combination with density functional theory calculations to study the redox stability of a nickel/yttria-stabilized zirconia solid oxide fuel cell anode. The results reveal that the transfer of oxygen from NiO to yttria-stabilized zirconia triggers the reduction reaction. During Ni reoxidation, the creation of a porous structure, due to mass transport, accounts for the redox instability of the Ni-based anode. Both the expansion of NiO during a redox c

Electrocatalytic properties of Ca, Sr, Mg, Fe, Co and Ni substituted lanthanum chromites deposited on 8YSZ lelectrolytes were studied using I/V and impedance techniques. The studied parameters were: the sintering temperature, the polarization, the gas and the anode composition. The polarization resistance depended much on these parameters. Also, a direct relationship between the electric conductivity, the catalytic and the electrocatalytic activities was evidenced. The electrocatalytic behavior followed the

The current study evaluates integrating fuel cell technology into the batteries as an alternative for internal combustion engines (ICEs) for Unmanned Aerial Vehicles (UAV). To further improve the performance of the UAV, a turbocharger is also integrated to ...

Progress on anode supported cell stacks (SOFCONNEX design, 50 m2 per cell) is presented. A 6-cell stack and a 8 cell-stack were mounted and tested with hydrogen fuel at 800 degre C, yielding 100 W el and 140 W el, corresponding to a power density of 1kW el/L (0.34 W/cm2). Fuel utilisation was 50% and electrical efficiency 25%. A one-cell stack delivered 0.4 W/cm 2 at 70% fuel utilisation and 33 % electrical efficiency, and showed a performance increase over its 450 h test period. Another one-cell stack was

In order to link electrochemical performance degradation of the cathode in a large solid oxide fuel cell (SOFC) to the presence of pollutant species, a spatially-resolved study of contaminants was performed. Distribution maps of pollutants over the cell allowed to identify their sources. Besides chromium and silicon, sulfur was found as a major pollutant species. Its preferential reaction with strontium doped lanthanum cobaltite (LSC), forming strontium sulfate SrSO4, compared to strontium doped lanthanum m

Microstructural evolution of anode supported solid oxide fuel cells (SOFC) during medium-term stack testing has been characterized by scanning electron microscopy (SEM). Low acceleration voltage SEM imaging is used to separate the three anode phases (nicke ...

This study aims to quantify in a holistic approach chromium (Cr) contamination in solid oxide fuel cell (SOFC) stack testing using adapted tools: i) a hot gas sampling method to analyze volatile Cr species in the air flux at the cathode inlet location; ii) a rapid quantification method for Cr as condensed matter in cathode material of post-test samples. The hot air sampling method reveals itself as a reproducible and time-resolved quantification technique for Cr trace amounts in a gas flow; this technique i

Chemical diffusion (D) and surface exchange (k) coefficients for SrFeO3-delta were measured using an electrochemical cell combined with electrochemical impedance spectroscopy (EIS) and potential step technique (PS) in the temperature range of 850-915°C. A value of ~ 4x10-5 cm2/s and a k value of ~ 8x10-5 cm/s were obtained at 900°C. Slow scan (0.5-3 microV/s) cyclic voltametry (CV) was performed in the same temperature range, using the same electrochemical cell to obtain oxygen nonstoichiometry data. The ox

The global demand for fossil fuels in the transportation sector is increasing rapidly due to the continuous growth of internal combustion engine vehicles. This leads to severe environmental problems, including greenhouse gas emissions and air-quality deter ...

Ni-YSZ anode supports show a fundamentally different microstructure from screenprinted Ni-YSZ anodes on YSZ electrolyte supports. Of high density and composed of fine zirconia and nickel oxide to allow for cofiring with a thin zirconia electrolyte film (5 µm), the anode support shows advantages of adequate strength and increased electrochemical activity probably not only limited to the TPB, unlike screen printed porous anodes. Areas up to 100 cm2 have been fabricated. Electrochemical cell testing produced r

In this study, we examine the parameters that govern the overall oxygen flux through a permeation membrane. The chemical diffusion (D) and the surface exchange (k) coefficients for oxygen in La0.6Sr0.4Fe0.8Co0.2O3-d were determined as a function of temperature using a specially designed electrochemical cell combined with impedance spectroscopy. Typically, D=1.7 10-5 cm2/s and k=3.6 10-4 cm/s in air at 900°C. These values were compared with literature 18O/16O isotope exchange data. Oxygen permeation measurem

Solid Oxide Fuel Cells (SOFC) is an interdisciplinary technology by excellence, necessitating combined knowledge and R&D from mechanical, chemical, electrical and materials science engineering. At LENI Laboratory at EPFL, SOFC cells and stacks are designed, tested and analysed in collaboration with industry, from small area single cells to now kW-range stacks integrated in a system. The hardware R&D effort is strongly assisted by, and dependent on, modeling activities, for both design (e.g. new geometries)

Recent progress in our development of anode supported electrolyte (ASE) SOFcells is reported. The cells are fabricated by cocasting of aqueous slurries of NiO/YSZ and 8YSZ, followed by cofiring. A gradient cathode is deposited by screenprinting successive layers of LSM/YSZ composite and lanthanum cobaltite, followed by a 2nd firing step. Full cells show a final thickness of ? 0.25 mm, high flexibility and reasonable warpage. Proper anode current collection is crucial and obtained by cofiring an additional o

Proton Exchange Membrane Fuel Cells (PEMFCs) are known as a promising alternative for internal combustion engines (ICE) to reduce pollution. Recent progress of PEMFCs is heading towards achieving higher power densities, reducing the refueling time, and dec ...

Electrochemical and mechanical aspects in solid oxide fuel cell stack must be understood to meet the reliability targets for market implementation. This study presents a stack modelling framework that combines thermo-electrochemical models, including degra ...

Cell durability is a crucial technological issue for SOFC commercialization, and considerable progress has been made in recent years. A number of degradation pathways have been established, amongst which microstructural changes, poisoning effects and forma ...

The Laboratory for Applied Mechanical Design (LAMD) designed, manufactured, and experimentally tested a novel steam-driven anode off-gas recirculation (AOR) fan for 10 kWel solid oxide fuel cell (SOFC) systems. Due to the dynamic steam-lubricated bearings, the AOR unit is expected to have a high lifetime, even at elevated rotational speeds and temperatures. Additional, the unit is oil-free, explosion-proof, very compact, and cheap to manufacture. The AOR fan diameter is at 19.2 mm and the nominal rotational

Jan Van Herle

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Generalized model of planar SOFC repeat element for design optimization

Modeling and experimental validation of solid oxide fuel cell materials and stacks

Solid oxide fuel cell anode degradation by the effect of siloxanes

In situ redox cycle of a nickel-YSZ fuel cell anode in an environmental transmission electron microscope

LaCrO3-Based Anodes for Methane Oxidation

Performance evaluation and the implementation of the turbocharger, fuel cell, and battery in Unmanned Aerial Vehicles (UAVs)

Compact 100 W stacks using thin components of anode supported cells and metal interconnects

Sulfur as Pollutant Species on the Cathode Side of a SOFC System

Nickel-Zirconia Anode Degradation and Triple Phase Boundary Quantification from Microstructural Analysis

Multi-Scale Assessment of Cr Contamination Levels in SOFC Cathode Environment

Oxygen transport and nonstoichiometry in SrFeO3-delta

Fuel cell-battery hybrid systems for mobility and off-grid applications: A review

Anode Supported Thin Zirconia Based Cells for Intermediate Temperature SOFC

Oxygen transport through dense La0.6Sr0.4Fe0.8Co0.2O3-d perovskite-type permeation membranes

Solid Oxide Fuel Cell

Stability and performance of tape cast anode supported electrolyte (ASE) cells

Progress in the Proton Exchange Membrane Fuel Cells (pemfcs) Water/ Thermal Management: From Theory to the Current Challenges and Real-time Fault Diagnosis Methods

Mechanical reliability and durability of SOFC stacks. Part I: Modelling of the effect of operating conditions and design alternatives on the reliability

TEM investigation on zirconate formation and chromium poisoning in LSM/YSZ cathode

Design and Experimental Realization of a Steam-Driven Micro Recirculation Fan for Solid Oxide Fuel Cell Systems