Дисертації з теми "Combustible solide"
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Mountadir, Soukaina. "Élaboration d'une pile à combustible à oxyde solide basse température à électrolyte bicouche." Electronic Thesis or Diss., Centrale Lille Institut, 2023. http://www.theses.fr/2023CLIL0019.
The conduction properties of yttrium-stabilized zirconia (YSZ) require operating temperatures of 700°C or higher for solid oxide fuel cells (SOFC). Very good performances were reported in the literature on bilayer electrolyte cells based on gadolinium-doped ceria (GDC) and bismuth oxide partially substituted with erbium. In this study, we considered this concept in order to develop a full cell. First, the conditions for the deposition of a thin layer (< 5 µm) of bismuth oxide of Er0.5Bi1.5O3 composition (ESB) on a dense substrate of (GDC) were optimised. Spin coating was chosen as the deposition technique. The composition of an ethanol-based ink was optimised and allowed to obtain dense layers, without crack, with a controlled thickness of a few microns. A La0.6Sr0.4MnO3/ Er0.5Bi1.5O3 (La0.6/ESB) composite was selected as cathode material. After optimisation of its deposition conditions by screen printing and characterisation by impedance spectroscopy on symmetrical cells made of an ESB electrolyte, full cells were prepared by deposition of a dense layer of ESB on half-cells supported by an anode with GDC as electrolyte, on the one hand, and an anode with YSZ as electrolyte, on the other hand. While the fragility of the ceria-based cells did not allow their performance to be measured, the study confirmed increased performances for the Ni-YSZ|YSZ|ESB|ESB-La0.6|La0.6 cell compared to the same cell without ESB layer
Roussel, Denis. "Optimisation d’architecture d’électrode poreuse pour pile à combustible à oxyde solide." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI019/document.
This project is involved in the development of new green power sources. Solid Oxide Fuel Cells (SOFCs) can achieve an output power of 1kW to 2MW and an energy conversion of up to 70%. Temperatures between 700 and 1000°C are required. A typical cell is made of an electrolyte sandwiched between two porous electrodes (anode and cathode). Porous electrodes are elaborated from ceramic powders and are critical components of the whole structure. These electrodes need to be porous enough to optimize gaz diffusion and electrochemical reactions. This requirement is antagonist to the need of a good mechanical strength. This conflict could be solved using hierarchical or anisotropic electrode microstructures. The aim of this thesis is to investigate possible ways to optimize an electrode. Numerical simulations and nanotomography characterizations are used for this purpose. Electrodes are elaborated using two different protocoles leading to anisotropic and isotropic porosities. Anisotropic samples are prepared by freeze-casting from a slurry of YSZ and LSM, which are typical materials for SOFCs. Freze-casting leads to a hierarchical porosity. The overall porosity is controlled by the loading of the slurry. The microporosity decreases with sintering temperature and the macropore size is function of the freezing rate. Isotropic samples are processed using pore formers. The size and the amount of pore formers are selected to match the characteristics of the anisotropic samples. These electrodes are characterized with Archimedes technique to determine the porosity, and with scanning electron microscope (SEM) to obtain the size of macropores. Three dimensional images of the microstructures are captured using focused ion beam (FIB-SEM tomography) technique (10nm} resolution) and using X-ray nanotomography (75nm} resolution). The overpotentials in an electrode depend on different parameters: composition of YSZ/LSM, porosity, particle sizes, electronic/ionic conductivities and electrochemical resistance. These parameters are studied on numerical microstructures coupled with a resistor network. These numerical microstructures have been generated at th scale of particles, using a numerical code based on the discrete element method (DEM). Simulations can be used to determine the limiting factor on the effective conductivity. For example, we show that the composition of YSZ/LSM in a sample matters little for electrodes below a certain thickness. A new method has also been developed to compute the effective conductivity from a FIB-SEM image taking into account the electrochemical resistance at the triple point boundaries between gaz, YSZ and LSM. The mechanical response of the elaborated microstructures are tested in compression up to the fracture. In parallel, DEM simulations are performed to simulate mechanical properties based on 3D images. The mechanical behaviours of homogeneous samples (with pore formers) and anisotropic samples are compared. The yield strength and stiffness are overestimated by simulations. Qualitatively, experimental results and simulations show consistent failure mecanisms. Moreover, the yield strength and stiffness are different in the two types of sample (anisotropic and isotropic). Such an anisotropy could be used to optimize mechanical properties in one direction
Rosini, Sébastien. "Capteur potentiométrique tout solide pour le dosage de l'hydrogène dans l'air." Grenoble INPG, 2003. http://www.theses.fr/2003INPG0028.
Novel-Cattin, Frédéric. "Élaboration et étude de pile à combustible selon la technologie électrolyte polymère solide." Grenoble 1, 1990. http://www.theses.fr/1990GRE10115.
Dessertenne, Estelle. "Matériaux solide conducteur thermodurcissable : Application aux plaques bipolaires pour pile à combustible." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00808869.
Princivalle, Agnès. "Nouvelle électrode à gradients pour piles à combustible à oxyde électrolyte solide." Grenoble INPG, 2006. http://www.theses.fr/2006INPG0142.
The objective of this thesis is related ta the synthesis and the structural, morphological and electrochemical characterization of cathodes to be used in the domain of solid oxide fuel cells (SOFC) operating at temperature ta 700°C ta ensure its industrialization. We have chosen ta carry out a composite cathode with continuous graded of porosity and composition, starting From typical materials: such as yttria-stabilized zirconia (YSZ) and lanthanum strontium manganite (LSM). The purpose of the addition o. F YSZ is to improve adhesion with the electrolyte (YSZ) and ta enlarge the triple contact area, where the gas, the electrocle and the electrolyte are in contact. For that, we have developed a new technique of synthesis, unique in France, the electrostatic spray deposition and undertook an original study of optimization of the microstructure of these new cathodes
Deseure, Jonathan. "Modélisation de cathodes de piles à combustible à oxyde électrolyte solide (SOFC)." Grenoble INPG, 2003. http://www.theses.fr/2003INPG0081.
Mosdale, Renaut. "Etude et développement d'une pile à combustible hydrogène/oxygène en technologie électrolyte polymère solide." Grenoble INPG, 1992. http://www.theses.fr/1992INPG0116.
Ciria, matamoros Desirée. "Propriétés thermo-mécaniques des matériaux pour les piles à combustible." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC064/document.
Solid oxide fuel cells (SOFCs) offer a real alternative to classical technologies for the generation of electricity by clean, efficient and environmental-friendly means. Nevertheless, the main limitation of SOFCs lies in their unsatisfactory durability and reliability due to the high operating temperatures and thermal cycling characteristic of these devices. An intense search is currently underway for materials for SOFCs with the objective of lowering the working temperature and then overcoming these limitations. Among the different candidates which have emerged, Lanthanum Silicate (LSO) and Yttrium-doped Barium Zirconate (BZY) were considered as potential alternatives to be used as electrolyte materials for SOFC at intermediate-temperature. While numerous studies have been devoted to characterizing and optimizing the microstructural and electro-chemical properties of SOFC components, as yet there is little research available on mechanical properties and the influence they have on SOFC lifespan.The reliability and durability of these devices depends not only on their electro-chemical stability, but also on the ability of their structure to withstand residual stresses arising from the cell manufacturing process and mechanical stresses from operation. Owing to the fact that SOFCs are composed by stacking of several single cells which in turn are made up of individual brittle layers in close contact, these stresses mainly originate from the difference between the coefficient of thermal expansion and elastic properties of adjacent layers and creep deformation. Mismatched stresses can result in the mechanical failure of a single cell and have dramatic consequences on the whole stack. Therefore, knowledge of mechanical properties of the cell components becomes an important issue for the mechanical integrity and development of SOFCs.The aim of this PhD thesis is the fabrication and structural, microstructural and mechanical characterization of LSO and BZY
Couture, Guillaume. "Nouveaux copolymères fluorés pour membranes de pile à combustible alcaline à coeur solide." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2013. http://www.theses.fr/2013ENCM0005/document.
The synthesis of polymeric membranes for solid alkaline fuel cells is the main topic of this work. These membranes have to exhibit several properties such as: a high hydroxide ion conductivity, a high thermal stability, a good chemical resistance especially to Hofmann degradation, a water-insolubility and mechanical properties suitable for the preparation of a membrane-electrode assembly. To fulfill these requirements, the use of alternated copolymers based on chlorotrifluoroethylene and vinyl ethers (poly(CTFE-alt-VE)) bearing quaternary ammonium groups has been considered. First, various functional or functionalizable vinyl ethers have been synthesized by palladium-catalyzed transetherification with a conversion rate higher than 80%. These monomers have been successfully copolymerized with CTFE and the good alternation of these monomers has been evidenced by elemental analysis and NMR spectroscopy. Furthermore, their physical, chemical and thermal properties have been studied by several techniques. Various functionalization steps have been carried out, yielding original poly(CTFE-alt-VE) copolymers bearing quaternary ammonium groups non sensitive to Hofmann degradation and with high thermal stabilities suitable for fuel cells. To improve the mechanical properties of these materials, terpolymers containing an increasing amount of 1H,1H,2H,2H-perfluorodecyl vinyl ether have been synthesized. Such terpolymers exhibited higher molecular weights, lower glass transition temperatures, and improved film-forming properties compared to the equivalent copolymers
Helfen, Arnaud. "Élaboration et caractérisation d'un nouvel électrolyte solide pour les piles à combustible : δ-Bi2O3". Marne-la-Vallée, 2004. https://tel.archives-ouvertes.fr/tel-00351659.
With an aim of finding a new electrolyte for the SOFC functioning at lower temperatures, we were interested in the new electrochemical synthesis of the delta phase of bismuth oxide. δ-Bi2O3 is a well-know high oxide-ion conducting material, but its narrow temperature range of stability, 729-825°C, had limited its application. The electrochemical method suggested by Switzer et al. Enables to stabilize this phase at room temperature. The study of δ-Bi2O3 becomes interesting again for an application such as solid electrolyte in full cell. Firstly, the influence of the electrochemical synthesis parameters of the δ-Bi2O3 thin layers was studied. It was deduced that a temperature of more than 50°C was necessary and that the optimal temperature deposition was 65°C. The bath pH value must be higher than 14. The current density, during the electrodeposition, was about 2. 25 and 3 mA/cm2. Using the XRD and TEM, the polycristalline structure of δ-Bi2O3 was confirmed. Both XRD measurements and TEM observations indicated an existence of a grain size of about 100 nm in these films. HRTEM images revealed nanocrystallites 10-20 nm in size. Their nanocrystalline natures stabilize the δ-Bi2O3 at room temperature. Using the EQCM, we have shown that the thickness of electrodeposited -Bi2O3 could not exceed 2 µm. Our stability study shown that the electrodeposited δ-Bi2O3 films exhibit a high long-time stability and that the δ-Bi2O3 keeps its fcc structure up to an annealing temperature of 340°C, above which it transforms into the sillenite structure. We have shown also that it is possible to make single crystalline nanowires of δ-Bi2O3, but the optimal conditions of electrodeposition synthesis were not determined. Lastly, the first measurements of conductivity were carried out. The preliminary results shown an ionic behaviour of our deposits, but we have some preoccupations for the reproducibility
Guindet, Jacques. "Contribution à l'étude de matériaux d'anode pour pile à combustible à oxyde électrolyte solide." Grenoble INPG, 1991. http://www.theses.fr/1991INPG0073.
Saoutieff, Elise. "Elaboration de couches de protection pour interconnecteurs de piles à combustible à oxyde solide." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2010. http://tel.archives-ouvertes.fr/tel-00606527.
Helfen, Arnaud. "Elaboration et caractérisation d'un nouvel électrolyte solide pour les piles à combustible : δ-Bi2O3". Phd thesis, Université de Marne la Vallée, 2004. http://tel.archives-ouvertes.fr/tel-00351659.
Brahim, Cyrine. "Conception et performances électrochimiques de matériaux nanostructurés pour piles à combustible à oxyde solide." Phd thesis, Paris 6, 2006. http://pastel.archives-ouvertes.fr/pastel-00002545.
TOUNSI, ABDESSAMAD. "Etude d'optimisation de l'electrode a oxygene pour piles a combustible a electrolyte polymere solide." Paris 6, 1994. http://www.theses.fr/1994PA066450.
NAIMI, YOUSSEF. "Etude d'optimisation de l'electrode a hydrogene des piles a combustible a electrolyte polymere solide." Paris 6, 1994. http://www.theses.fr/1994PA066415.
Flandre, Xavier. "Nouvelles électrodes pour pile à combustible à oxyde solide et électrolyseur à haute température." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10182/document.
In the current context, fossil energy resources decrease and become more expensive, in addition to environmental concern. In this frame, solid oxide fuel cells (SOFC) are a promising green alternative energy source. Reversibly used, this system can also allow storage of electricity produced intermittently through the electrolysis of water. However, several bottlenecks still remain in terms of performances and stability of materials currently used to improve their lifetime and decrease their working temperature. In this doctoral thesis, our contribution focused on two cathode materials for SOFCs, Ba2Co9O14 and Ca3Co4O9+δ, and compounds derived from La4Ti2O10 which may be relevant as anode material. Our study mainly focused on the understanding of the physicochemical mechanisms involved in these materials by using impedance spectroscopy. For cobaltites, this study has led to the identification of the limiting parameters and will help the future optimization of complete stacks with better performances. For the La4Ti2O10 derived phases with the cuspidine structure, a neutron scattering study confirmed the oxygen diffusion mechanisms in these materials. However, their conductivity and catalytic properties remain insufficient to hope to use these compounds as SOFC’s anode, unlike other lanthanum titanates which display a layered perovskite structure
Vernoux, Philippe. "Reformage interne progressif du méthane dans les piles à combustible à oxyde électrolyte solide." Grenoble INPG, 1998. http://www.theses.fr/1998INPG0155.
Briois, Pascal. "Synthèse par pulvérisation cathodique et caractérisation d'électrolytes solides en couches minces pour piles à combustible à oxydes solides (SOFC) fonctionnant à température intermédiaire." Vandoeuvre-les-Nancy, INPL, 2005. http://docnum.univ-lorraine.fr/public/INPL/2005_BRIOIS_P.pdf.
The major problem of Solid Oxide Fuel Cells (SOFC) is their operating temperature. One challenge is to decrease this temperature from 1000 to 700°C, this is the Intermediate Temperature –SOFC technology. It's very important to decrease the thickness of the ionic conductor to reduce its resistance. In this context, the reactive magnetron sputtering is a powerful technique for elaborating the coating with a compatible thickness with the application (~ 5-10 µm). After a description of the experimental device and of some specific analysis methods for this study, we present some results about the materials reference of the SOFC, the Yttria Stabilised Zirconia (YSZ). Then, we present some results about two new materials with higher ionic conductivity of oxygen than YSZ at 700°C: Gadolinia Doped Ceria (GDC) and Lanthanum Molydenum Oxide (LAMOX). At last, we present first results on the synthesis of the bilayer electrolyte coating: GDC/YSZ
Akrour, Laurent. "Membrane échangeuse anionique et application en pile à combustible." Paris, CNAM, 2005. http://www.theses.fr/2005CNAM0493.
The objective of this study is to produce an anion exchange membrane being able to be used in an alkaline fuel cell with alkaline polymeric solid electrolyte. The quaternaryammonium groups formed by the DABCO and quinuclidine shows a good resistance to thermal degradation. The membranes synthetised from the polyépichlorhydrine, the copolymer polyépichlorhydrine-allyl glycidyl ether and the two preceding amines are crosslinked by thermal and photochemical way. The photocrosslinked membranes have an ionic exchange capacity of 1,3 mèq/g and a conductivity of about 8. 10[puissance]-2 S/cm at 25°C in KOH 2,5M. The interfaces electrode-membranes studied under oxygen and hydrogen, with an half-cell assembly, were optimized and make it possible to produce an alkaaline fuel cell with membranes developing a maximum power of about 100 mW/cm2 under H2/O2 at 25°C and 12mW/cm2 with a methanol-KOH 4M mixture at 25°C
Constantin, Guillaume. "Interfaces et durabilité d'un coeur de pile à combustible à oxyde solide fonctionnant à température intermédiaire." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00845631.
Agel, Eric. "Electrode à air électrolyte solide polymère alcalin pour piles à combustible et générateur métal-air." Paris 7, 2002. http://www.theses.fr/2002PA077002.
Jamard, Romain. "Systèmes catalytiques pour pile à combustible alcaline à électrolyte solide alimentée en borohydrure de sodium." Poitiers, 2009. http://www.theses.fr/2009POIT2284.
The present work is concerned with the search of adapted catalyst for Direct Borohydride Fuel Cell. First, a reference system is developed. It was necessary for the reliability of this method of manufacturing the anode to obtain reproducible performances. This reference system has shown a problem of fuel stability, which spontaneously hydrolyzes at the anodic catalyst. On the other hand, aging tests showed that the decrease in cell potential over time was associated with damages of cathode and electrolyte. At the anode, the use of iridium nanoparticles deposited on carbon leads to a reduction of the parasitic reaction (hydrolysis of sodium borohydride) and therefore increases the faradic efficiency of the DBFC. According to the study of the oxygen reduction reaction in alkaline medium on different metallic macrocycles, it has been shown that iron phtalocyanine deposited on a carbon Vulcan XC72 has excellent activity for this reaction. Moreover, this catalyst seems very tolerant to the presence of sodium borohydride. A DBFC working with this material as cathodic catalyst has achieved excellent performances and stability
Claude, Eric. "Nouveaux catalyseurs organométalliques pour la cathode de la pile à combustible à électrolyte polymère solide." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0127.
Laurencin, Jérôme. "Fonctionnement sous méthane d'une pile à combustible "SOFC" (Solid Oxide Fuel Cell) : optimisation des performances et de la durabilité." Grenoble INPG, 2008. http://www.theses.fr/2008INPG0087.
Rampon, Régine. "Elaboration et optimisation d'électrolytes pour piles à combustible de type SOFC." Besançon, 2007. http://www.theses.fr/2007BESA2017.
The high operating temperature of the SOFC decreases the life time of the cells. The reduction of the SOFC operating temperature causes several problems such as ohmic drop through the electrolyte. To overcome these cell performance losses, the electrolyte resistivity can be decreased by lowering the thickness of the electrolyte. The chosen process is the plasma jet projection of ceramics suspensions. A good understanding of the process is necessary in order to control the coatings microstructure. First the interactions between the suspension characteristics, the injection and the projection process have been studied. Dispersed and stable suspensions have been obtained in three different solvents: distilled water, methanol and ethanol/methylethylketone azeotrope. Solvent nature determines the surface tension and viscosity is controlled through additive amounts. Atomization has been studied as a function of the suspension formulations. Suspension with water generates monomodal drop size distribution when its viscosity is high or the atomization gas flow rate is low. Suspensions with alcohol generate wide drop size distribution. This work gave trends about suspension behaviour toward atomization and allowed us to make hypothesis about drop trajectory in the plasma. Finally study of the coating microstructure showed that using water as solvent and working with low atomization gas flow rate generate the less porous microstructure. Influence of operating parameters such as plasma characteristics, cinematic and projection distance has been evaluated. Particle temperatures and speeds were measured with accuraspray and used as a tool to select the best operating parameters in order to obtain less porous coatings. It was really difficult to obtain dense coatings so in situ thermal treatment was studied and preliminary tests are presented. Coatings were produced and then treated by passing the plasma in front of the coating. Coating surfaces are obtained really dense but are cracked. Finally first electrochemical results are presented
Baran, Sümeyra Seniha. "Les hydrochars de déchets de paille de lavandin valorisés comme combustible solide et comme matériau adsorbant." Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5003.
The Provence-Alpes-Côte d'Azur region in the south-east of France has been one of the main production centres of the perfume and cosmetics industries for centuries. The extraction of Lavandin yields 100 kilograms/ha of essential oil, while a large amount of solid waste, known as lavandin distilled straw, is generated. The objective of this thesis work was to explore economic and environmental friendly valorisation routes of this waste in order to convert it into high value-added products.For that, Lavandin straws (L) waste was submitted to hydrothermal carbonization (HTC) in order to get a carbonaceous material called hydrochar. The valorisation of Lavandin straw (L) and its hydrochars as solid fuel and adsorbent was investigated in this thesis.For the production of fuel, the L was subjected to HTC at various temperatures (180 to 260ºC) and retention times (1 to 20 h). In order to evaluate the quality of hydrochars as solid fuel, fuel properties were evaluated according to the severity factor calculated based on HTC temperature and retention time. The obtained hydrochars presented fuel properties close to sub-bituminous coal and lignite.For the valorization of Lavandin as adsorbent, the most suitable hydrochar for adsorption was selected. Adsorption of Ni(II), Cd(II), Pb(II) on L, hydrochar, NaOH- and HNO3-modified hydrochar was studied as a function of contact time, pH, initial single concentration of metal, initial mixed concentrations of metals. Pb(II) was more efficiently adsorbed than Ni(II) and Cd(II), on all adsorbents. When metals were simultaneously present, surface competition occurred. Surface modifications using NaOH or HNO3 improved the adsorption capacity of hydrochar, but the production yield of modified hydrochar was low when high concentration of acid was used for the surface modification.Lavandin straw can be valorised as solid fuel and adsorbent in an environmental and economic approach
Rembelski, Damien. "Développement d'une pile à combustible à oxyde solide de type monochambre fonctionnant sous mélange air/méthane." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00789963.
Sauvet, Anne-Laure. "Etude de nouveaux matériaux d'anode pour pile à combustible à oxyde solide (SOFC) fonctionnant sous méthane." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10096.
Rembelski, Damien. "Développement d’une pile à combustible à oxyde solide de type monochambre fonctionnant sous mélange air/méthane." Thesis, Saint-Etienne, EMSE, 2012. http://www.theses.fr/2012EMSE0679/document.
This study is devoted to the development of a single-chamber solid oxide fuel cell. Contrary to a conventional solid oxide fuel cell, a single chamber fuel cell works under a hydrocarbon/air mixture with no more sealing needed. The working principle of this device is based on the difference of catalytic activity between the anode and the cathode: the anode must be selective to hydrocarbon oxidation and the cathode to oxygen reduction. With single-chamber geometry, chemical stability of materials has to be taken into account under hydrocarbon/air mixture at high temperature.The goal of this work is to optimize the performances of a single-chamber cell working under methane/oxygen mixture and to improve this device comprehension.Each part of the cell (electrolyte, anode, cathode) was characterized under methane/oxygen mixture. Four cathode materials (LSM, BSCF, SSC, LSCF) were compared regarding their catalytic activity, stability, electrical conductivity and polarization resistance. The catalytic activity of the anode was studied in order to identify the chemical reactions happening. A study of electrolyte supported cells showed that LSCF material is the most suitable cathode. Furthermore, this study showed that the electrolyte was too thick; the anode supported configuration was studied. The first anode supported cell showed an inhomogeneous anode and a porous electrolyte. From that, a study of the homogeneity of the anode and the densification of the electrolyte was performed. A maximum power density of 160mW.cm-2 was obtained by optimizing the working conditions of the cells (temperature and CH4/O2 ratio)
Dumaisnil, Kévin. "Élaboration et caractérisations de matériaux de cathode et d'électrolyte pour pile à combustible à oxyde solide." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0396/document.
Energy made from fossil fuels, oil or coal, is becoming increasingly rare and its price will increase in the near future. Developing alternative energy sources could compensate the use of fossil fuel. Particularly, an alternative form of energy is being developed through fuel cells, through the production of electricity and heat from hydrogen. Fuel cells can provide low wattage (microwatts for sensor applications), medium wattage (kilowatts for residential applications) and high wattage (megawatts for the industry). A fuel cell consists of 3 components : 2 electrodes (anode and cathode) separated by an electrolyte. In my work, I use solid pxide materials for these three elements in order to expand on the literature of Solid Oxide Fuel Cell (SOFC). Commercialized SOFCs currently operate at very high temperatures, typically above 800°C. The objective of this study was to develop oxides that could decrease the working temperature of the cell to 600°C, which would allow the use of steel to contain these fuel cells. In order to enable the SOFC to operate at this temperature, it is imperative to decrease the electrical resistances of the two electrodes and electrolyte in order to collect a continuous voltage which is maximal at the terminals of the fuel cell, and also to have a high electric current going through the fuel cell. The cathode, in contact with the oxygen present in the atmosphere, is the most critical element to be optimized. I close as a cathode material La₀.₆Sr₀.₄Co₀.₈Fe₀.₂O₃ (LSCF), which has already been studied. As electrolyte, I used Ce₀.₉Gd₀.₁O₂ (CGO) which is known to work below 650°C. I synthesized these materials through the Pechini method, a soft chemistry sol-gel method. The materials were characterized by X-ray diffraction and scanning electron microscopy. An important aspect of this work was the electrical characterization using complex impedance measurements in a wide frequency range (0,05 Hz to 2 MHz) and temperature (300°C to 700°C). The best result was obtained with a 40 µm thick, porous, composite cathode (LSCF/CGO 50/50 wt%) was deposited by screen printing on a 1,5 mm thick and dense CGO ceramic. In addition, a dense thin film of LSCF with a thickness of about 0,1 µm was spin-coated between the cathode and the electrolyte to improve the interface. At 600°C the measured resistance of the cathode was 0,13 Ω for 1 cm² : this value is similar to the results found in the state of the art. An aging study of the cathode and the electrolyte was carried out at 600 °C for 1000 h in air : the resistance of the cathode increased of 32%. This may be related to the different values of the thermal expansion coefficients of the cathode and electrolyte materials
Celikbilek, Ozden. "Optimisation de la cathode pour pile à combustible à oxyde électrolyte solide : approches expérimentale et numérique." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI071/document.
Understanding, controlling and optimizing the mechanism of oxygen reduction reaction at the cathode need to be addressed for high performance energy conversion devices such as solid oxide fuel cells (SOFCs). Structured porous films of mixed ionic electronic conductors (MIECs) and their composites with addition of a pure ionic conductor offer unique properties. However, correlating the intrinsic properties of electrode components to microstructural features remains a challenging task. In this PhD thesis, cathode functional layers (CFL) of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and LSCF/Ce0.9Gd0.1O2-δ (CGO) composite cathodes with hierarchical porosity from nano- to micro-range are fabricated by electrostatic spray deposition technique. The films were topped with LSCF as a current collecting layer (CCL) by screen printing technique. A parametric optimization study was conducted experimentally in terms of particle size, composition, and thickness of CFL and CCL layers. The experimental results were supported by a numerical 3D Finite Element Model (FEM). Microstructural parameters determined by FIB-SEM tomography were used in a simple geometry similar to experimentally observed columnar features. In this work, experimental results and modelling were combined to provide design guidelines relating optimized electrochemical performances to the microstructure and bulk material properties. A complete fuel cell with optimized cathode film was tested in real SOFC operational conditions
Levesque, Caillol Noémie. "Elaboration, caractérisation et modélisation de cathode sérigraphiée, La₀. ₈Sr₀. ₂MnO₃, pour pile à combustible SOFC." Saint-Etienne, EMSE, 2006. http://tel.archives-ouvertes.fr/tel-00165173.
The properties of LSM screen-printed cathodes on YSZ electrolytes and the modelling of oxygen reduction have been studied. A bibliographic review of published works on LSM and LSM/YSZ interface reveals the lack of consensus over the mechanism proposed between oxygen and LSM. The different theoretic models possible and their associated kinetic laws are presented to serve as the basis for the kinetic modelling. Microstructural characterisations proved the adaptability of the screen-printing technique for making electrodes. The layers are stable in time and well reproducible. Their microstructure is homogenous and regular with a porosity of 0. 6. Physico-chemical characterisations were carried out. Infra-red spectrometry analysis and thermo-programmed desorptions have shown the existence of different kinds of oxygen-adsorbed species on LSM powder. A calorimetric study has revealed a change in the quantity of heat released during oxygen adsorption as a function of temperature. By XPS analysis on screen-printed layers, important strontium segregation was observed depending on pressure, temperature and polarisation conditions. From electrochemical characterisations made by impedance spectroscopy, three resistive contributions have been identified. Only the low frequency contribution, which is the only pressure sensitive contribution, was considered to correspond to an electrode phenomenon. Following a methodical study of the different modelling hypothesis, a mechanism for the cathodic reaction was obtained. The proposed model is complex. It is composed of three conductivity paths running in parallel (two surface paths and one bulk path). These paths involve two different oxygen species and their preponderance depends on pressure, temperature and polarisation conditions. A study of water vapour influence completes this work, to understand its impact on the cathode electrical performance. The benefits brought by water vapour are not linked to a direct catalytic effect, as it does not affect the apparent activation energy of the cathode's process. The experiments seem to indicate that the benefits are linked to the strontium segregation at the surface of grains. It seems water vapour helps maintain and regenerate the initial properties of the layer
Baudoin, Sylvain. "Étude d’un système hybride pile à combustible / microturbine dans un contexte microréseau rural isolé." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0440/document.
Rural areas, often far away from the main electric grid, are particularly suitablefor the deployment of microgrids (MG). This type of grid allows a restructuring oftoday's power grid in order to integrate more efficiently renewable power sources.Biogas, produced by anaerobic digestion of agricultural wastes, is a renewable energyresource available in rural areas. This resource, easily stored in large quantities, isparticularly interesting for weak grids like a MG. Energy sources using biogas are morereliable and less dependent on stochastic phenomena such as wind or solarillumination.After a state of the art on the different technologies enhancing biogas, it is clearthat a hybrid system consisting of a SOFC type fuel cell and a microturbine (MT)achieves the best electric efficiency with low environmental impact.The overall objective of the thesis is to study the SOFC / MT system as themain power source in an isolated rural MG context. For this purpose, a model of thesystem was carried out by focusing on the elements that affect the dynamics of thesystem's electrical signals. The hybrid system was then sized in order to maintainoptimal electrical performance, and a unique 3LNPC multilevel converter is used tointegrate the hybrid system to the MG. As a fuel cell is sensitive to load changes(affecting its performance and lifespan), the first objective of the control strategyapplied to the 3LNPC converter is to regulate the power of the SOFC at its nominalvalue. The MG must be able to operate autonomously when islanded, thus the secondobjective of this strategy is to set the grid voltage and frequency.The controllers of the control strategy are designed paying particular attention tothe robustness. The operation of the SOFC / MT hybrid system, driven by a single3LNPC type converter equipped with an innovative control strategy, has been testedand validated in simulation and experimentally in the MG platform of ESTIAResearch
Greiner, Yoan. "Nouvelles architectures tridimensionnelles pour électrodes de piles à combustible à oxydes solides (SOFC Solid Oxide Fuel Cell)." Thesis, Littoral, 2017. http://www.theses.fr/2017DUNK0496.
Fuel cells are systems that convert chemical energy directly into electrical energy. The physical structure of a fuel cell is composed of a porous cathode and anode separated by a dense electrolyte. Solid Oxide Fuel Cells (SOFC) offer an alternative for power generation and versability in their use. Current research focuses on lowering the operating temperature of this type of fuel cell (500-700°C) to increase their life, reduce manufacturing costs and damageto the interfaces. In order to compensate these problems, research tends towards materials with better electrochemical properties or by modifying the microstructure of the cathode to improve mass transfer and charge transfer. The cathode is a very important layer in the SOFC stack because it has a polarization resistance whose reduction is a major challenge to deal with. In a first part of this thesis work we have developed a method to improve the electochemical properties of strontium doped lanthanum manganite (LSM) cathodes. The second part was devoted to the elaboration and caracterization by impedance spectroscopy of SOFC symmetric half-cells with a LSM-based composite material allowing to improve the electochemical properties of electrodes at temperatures between 600-700 °C
Girona, Kelly. "Modélisation et validation expérimentale du comportement électrochimique d'une pile à combustible SOFC en reformage interne de biocombustible." Grenoble INPG, 2009. http://www.theses.fr/2009INPG0050.
This work is dedicated to the study of SOFC operation directly on biogas (mixture of humidified methane and carbon dioxide). More specifically, it concerns the optimization of biogas internal dry reforming conditions. A special attention is paid to the carbon deposition risk. The first part of this work is dedicated to the development of numerical tools in order to determine the risk of carbon formation within the anode during the operation. Thermodynamic and kinetic calculations have been achieved allowing the determination of safe operation conditions (temperature, fuel composition and cell polarization). The second part of this work concerns the study of carbon deposition within the anode material (Cermet Ni-YSZ). The performance degradation upon operation due to carbon deposition has been studied over more than hundred hours on complete cells by electrochemical impedance spectroscopy. A diagram analysis protocol has been specially developed. The carbon deposited has been characterized by scanning electron microscopy with particular attention given to its morphology and distribution. The analyses of all the above results allowed proposing carbon deposition mechanisms. To end, the cell operation under biogas is shown to be relevant as well as the dedicated numerical approach developed in this work
Lévêque, Guillaume. "Matériau de type apatite pour pile à combustible : élaboration, caractérisations électrique et structurale, mise en forme." Limoges, 2012. https://aurore.unilim.fr/theses/nxfile/default/635e1c5f-cf50-4f44-88fe-c41a8c231096/blobholder:0/2012LIMO4004.pdf.
This work is devoted to elaboration, structural study, shaping and ionic conductivity properties of oxyapatites of general formula La9. 33±x(SiO4)6O2±1. 5x for potential applications as electrolyte in Solid Oxide Fuel Cells (SOFCs). The physic, chemical and thermal behavior of La2O2CO3 reagent was first studied in order to further synthesize pure apatite powders with variable stoichiometry (0 < x < 0. 34) using a solid state route. The structural study of synthesized and referenced powders were performed. Dense ceramics (more than 99% of the theoretical value) were obtained by using natural sintering, after isostatic pressing. Their electrical properties confirmed the clear increase of the ionic conductivity values with the oxygen atoms excess in the apatite structure. The obtained values remain insufficient for the electrolyte application but remain promising because the apatite grains present values of 2. 55. 10-2 S/cm at 700°C. Shaping studies by tape casting allowed obtaining high density pellets (more than 99% of the theoretical value). An exploratory study by suspension plasma spraying brought to light the possibility to synthesize directly from the reactives layers of apatite materials
Thommy, Léonard. "Développement de nouveaux matériaux d’électrodes pour convertisseurs électrochimiques à haute température : piles à combustible et électrolyseurs." Nantes, 2015. http://archive.bu.univ-nantes.fr/pollux/show.action?id=7f5a6fca-209c-49d4-b02e-4d6eef28f439.
The aim of this work is the development of new materials for the negative electrode of solid oxide fuel cells and electrolysers (SOFC and SOEC), showing a good electrocatalytic activity at intermediate temperatures. New BaIn0,3Ti0,7O3±δ-derived compounds Ba0. 5La0. 5Ti0. 3Mn0. 7O3 (BLTM) and Ba0. 5La0. 5In0. 3Ti0. 1Mn0. 6O3 (BLITIM) were developed in a first part of this work. Ni-BLTM/BIT07 et Ni-BLITIM/BIT07 symmetrical cells were fabricated by tape casting and co-sintering, and were optimised. A polarisation resistance (Rp) value of 0,20 Ω cm2 has been measured at 700°C under Ar/H2 (5%), for a nominal NiO-content of 40%m. In a second part of this work, new MIEC compound family derived from La0. 75Sr0. 25Cr0. 5-xMn0. 5O3-δ (LSCM) by substitution of ruthenium have been prepared. The introduction of ruthenium increased the total conductivity of the compound under both air and reducing atmosphere. The performances of La0. 75Sr0. 25Cr0. 4Mn0. 5Ru0. 1O3-δ (LSC0. 4MRu0. 1) as an anode material have been investigated in symmetrical cells with Ce0. 9Gd0. 1O1. 95 as electrolyte material, and compared to that of La0. 75Sr0. 25Cr0. 5Mn0. 3Ni0. 2O3-δ (LSCM0. 3Ni0. 2), LSCM, and LSCM impregnated with nickel. A metallic particle dispersion has been obtained at the surface of LSCM0. 3Ni0. 2 et LSC0. 4MRu0. 1 and it has been shown to improve a the part of the Rp linked to gas adsorption. The best performances have been obtained for LSC0. 4MRu0. 1. The comparison of the results obtained under Ar/H2 5% and under methane along with a comparison of the cell ageing allowed us to evaluate and discuss the interest of exsolution
Maillard, Frédéric. "Influence de la structure d'électrocatalyseurs nanodispersés sur les réactions impliquées dans une pile à combustion directe de méthanol." Poitiers, 2002. http://www.theses.fr/2002POIT2290.
PEMFCs appear as economically viable and methanol utilization is a promising approach. Methanol oxidation leads to a poisoning intermediate, adsorbed CO, which dramatically reduces the PEMFC's performances. Methanol oxidation electrocatalysts were prepared from Ru electrochemical or spontaneous deposition on carbon-supported Pt nanoparticles. The maximum in electrocatalytic activity for methanol oxidation is observed with electrochemical deposits because of the presence of non-reducible ruthenium oxides in the spontaneous deposit. Two CO species are observed at the electrode surface, an exchange between these two CO species may occur. The formation of a PtRu alloy is not a required condition for efficient methanol electroxidation. The solid electrolyte being permeable to methanol, the cathode is depolarised. A particle-size effect on oxygen reduction reaction kinetics with or without methanol is observed. As particle size decreases, the catalysts are more methanol tolerant. Based on particle size considerations, Pt:Cr appears to be a more active catalyst than Pt for oxygen reduction in methanol-containing electrolyte
Chesnaud, Anthony. "Oxy-gallates et oxy-germanates de terres rares conducteurs par ions oxygène." Nantes, 2005. http://www.theses.fr/2005NANT2047.
Marchand, Olivier. "Etude du procédé de projection plasma de suspensions pour l'élaboration de piles à combustible à oxyde solide." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2010. http://tel.archives-ouvertes.fr/tel-00597338.
Vibhu, Vaibhav. "Stabilité et vieillissement des études de nickelates base praséodyme comme cathodes pour oxyde solide piles à combustible." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0017/document.
This PhD work is dedicated to stability and ageing studies of Praseodymium based nickelates ascathodes for Solid Oxide Fuel Cells (SOFCs). With this respect Ln2NiO4+δ (Ln=La, Pr or Nd)compounds with the K2NiF4 type structure act as alternative cathode materials for IT-SOFC due totheir mixed ionic and electronic conductivity (i.e. MIEC properties). Pr2NiO4+δ shows excellentelectrochemical properties at intermediate temperature (i.e. low polarization resistance Rp value, Rp= 0.03 Ω.cm² at 700 °C), while La2NiO4+δ exhibits higher chemical stability. So, the properties ofLa2-xPrxNiO4+δ nickelates were investigated with the aim to find best compromise between chemicalstability and electrochemical performances. After synthesis, the physical and chemical properties aswell as their transport and electrochemical properties have been determined. Measurements of thepolarization resistance of symmetrical half-cells have been carried out by impedance spectroscopy.Then, the chemical stability and the electrochemical performance of the materials have been studiedfor duration up to one month. As an interesting point, even after complete dissociation of Pr2NiO4+δinto PrNiO3-δ,Pr4Ni3O10+δ and Pr6O11, the polarization resistance does not show significant change.So finally, two new materials PrNiO3-δ and Pr4Ni3O10+δ were investigated as SOFCs cathodeshowing very promising results for Pr4Ni3O10+δ in symmetrical cell (Rp (Pr4Ni3O10+δ) = Rp(Pr2NiO4+δ) = 0.15 Ω.cm² à 600 ° C) and complete cell (1.6 W.cm-2 at 800 °C)
Simões, Mário da Silva Correia. "Développement d'électrocatalyseurs anodiques plurimétalliques nanostructurés pour une application en pile à combustible à membrane alcaline solide (SAMFC)." Poitiers, 2011. http://nuxeo.edel.univ-poitiers.fr/nuxeo/site/esupversions/b019adc2-f6df-4414-a842-7e161cb5227f.
Solid Alkaline Membrane Fuel Cells are feasible alternatives to PEMFCs, allowing a wider choice of catalytic materials and fuels other than hydrogen, like small organic molecules and borohydrides. Several nanocatalysts were synthesized by a colloidal method and their activity and selectivity were studied toward the glycerol and NaBH4 electrooxidation in alkaline medium. Those catalysts are palladium based. Its interaction with Au, Ni and Bi were also evaluated. A Pt/C catalyst was also studied as well as its interaction with bismuth. PdAu/C catalysts presented a higher activity toward the glycerol electrooxidation than monometallic Au/C and Pd/C. This fact is explained by a synergetic effect between both metals that form ordered alloys. A bifunctional mechanism seems more appropriate to explain the increased activity of palladium rich PdNi/C catalysts. PdBi/C and PtBi/C are the most active catalysts for the glycerol oxidation due to adatom and bifunctional effects. The primary alcohol functions of the glycerol molecule are preferentially oxidized on Pd and Pt based catalysts. The production of hydroxypyruvate ion species was evidenced on Au/C catalyst. A mechanism was proposed for the NaBH4 oxidation on palladium, involving hydrolysis, hydrogen and borohydride oxidation steps. Pd0,5Au0,5/C and Pd0,5Ni0,5/C catalyst activities are similar to that of Pd/C. NaBH4 direct oxidation occurs on Pt0,9Bi0,1/C at low potentials without hydrogen evolution. Glycerol oxidation in alkaline fuel cell allows the cogeneration of electricity and high value added chemicals while NaBH4 oxidation allows for high energy and power density systems
Delahaye, Thibaud. "Réalisation et optimisation d'électrolytes et d'anodes pour piles à combustible à oxyde solide fonctionnant à température intermédiaire." Nantes, 2006. http://www.theses.fr/2006NANT2139.
This thesis shows the feasibility at the laboratory scale, of Solid Oxide Fuel Cells with the use of new materials. The new electrolyte, BaIn0. 3Ti0. 7O2. 85, exhibits an anionic mobility close to10-2 S. Cm-1at 700°C. This compound can be sintered efficiently (94% at 1350°C) and shows a good stability under operating conditions. A main part of this research is devoted to the anode material prepared as a Ni/BaIn0. 3 Ti0. 7O2. 85 cermet. This composite shows a controlled open porosity ≥ 40% and an electronic conductivity of 100 S. Cm-1 at 700°C for a Ni content of 18. 7 vol. % only. As part of the devopment of anodes working under natural gas, a specific treatment leads to stable cermets which do not suffer from carbon deposition. Complete cells have been prepared with the use of spray-pyrolysis, co-pressing and co-sintering techniques. A testing system has been designed and set up, which enabled to evaluate cell performances at 700°c under H2 et CH4
Vietoris, Thomas. "Etude de la combustion quasi stationnaire d'un combustible solide soumis à un écoulement parallèle à sa surface." Poitiers, 1999. http://www.theses.fr/1999POIT2312.
Miachon, Sylvain. "Développement d'une pile à combustible hydrogène/oxygène à électrolyte polymère solide de 100 cm2 à hydratation interne." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10048.
Petitjean, Marie. "Propriétés et réactivité de ferromanganites de lanthane strontium, cathodes de piles à combustible SOFC." Dijon, 2003. http://www.theses.fr/2003DIJOS057.
Radulescu, Mihai Nicolae. "Systèmes à cogénération d'électricité et de chaleur avec piles à combustible de type PEMFC ou SOFC et vaporeformage externe." Nancy 1, 2006. http://docnum.univ-lorraine.fr/public/SCD_T_2006_0095_RADULESCU.pdf.
The objectives of this PhD work concern the energy management in combined heat and power (CHP or cogeneration) systems using fuel cells and fed by natural gas. Firstly, we define the theoretical and effective efficiencies of such systems. Secondly, we study in a detailed way the operation of H-Power CHP units with a low temperature proton exchange membrane fuel cell (PEMFC) and steam reformer. We develop a model able to simulate the operation of the units in different conditions. We propose improvements that could lead to an electric efficiency increase by 3 to 10 percentage points. Finally, we compare these units with CHP systems using solid oxide fuel cell (SOFC) fed by natural gas. The high temperature fuel cell generates enough heat to ensure both the thermal conditioning of gases and the reforming of natural gas. We propose and study five hybrid system designs in order to value the thermal and chemical residual energies and to convert them mostly in supplementary electric energy
Radulescu, Mihai Nicolae Feidt Michel Lottin Olivier. "Systèmes à cogénération d'électricité et de chaleur avec piles à combustible de type PEMFC ou SOFC et vaporeformage externe." [S.l.] : [s.n.], 2006. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2006_0095_RADULESCU.pdf.