Synthesis and characterization of La2NiO4+δ coatings deposited by reactive magnetron sputtering using plasma emission monitoring

This work focuses on the structural and electrical characterization of La–Ni–O coatings deposited by reactive magnetron sputtering using Plasma Emission Monitoring (PEM) which allows high deposition rate. The optimal regulation setpoint for lanthanumdeposition is determined and then the current dissipated on the nickel target is adjusted to obtain the convenient La/Ni ratio to achieve the K2NiF4 structure. After an appropriate annealing treatment, all coatings exhibit crystalline structures that depend on the La/Ni ratio. Some cracks appear on samples deposited on alumina substrates depending to the argon flow rate and influence their electrical behavior

Synthesis of Half Fuel Cell Ni-YSZ / YSZ on Porous Metallic Support by Dry Surface Deposition Processes

A new cell design with metallic porous support was selected in order to face with the reduction of IT-SOFC's operation temperature. Nevertheless, the excessive roughness of the porous metallic interconnect induce additional problems when a thin electrolyte layer is required. In this work, an anode material (NiO-TSZ) by Atmospheric Plasma Spraying was deposited on metallic supports (ITM) produced by PLANSEE able to cover the roughness of the support. Then, a second thin and dense electrolyte layer (YSZ) by reactive magnetron sputtering was produced on the anode material. In this study, for both processing routes, the optimal process parameters regarding the structural, morphological and electrical characterizations were investigated

Ln 2 NiO 4+δ (Ln = La, Pr, Nd) coatings deposited by reactive magnetron sputtering as cathode material for intermediate temperature solid oxide fuel cell

This work focuses on the comparison of Ln-Ni-O coatings (Ln = La, Nd, Pr) deposited by reactive magnetron sputtering using Plasma Emission Monitoring (PEM) which allows high deposition rate. Each layer is deposited by different steps. The optimal regulation setpoint for oxide rare-earth deposition is determined and then the current dissipated on the nickel target is adjusted to obtain the convenient Ln/Ni ratio and to achieve the K2NiF4 structure. After an appropriate annealing treatment, all coatings exhibit crystalline structures, which depend on the Ln/Ni ratio. Due to the instability of Pr2NiO4 structure at intermediate temperatures, the crystallization step of praseodymium nickelate is performed at higher temperature than the other materials. This further thermal treatment implies a more porous structure. Each coating exhibits interesting properties. Electrical and electrochemical characterizations performed on these deposits prove better properties of the praseodymium nickelate coating

Experimental Activity Descriptors for Iridium-based Catalysts for the Electrochemical Oxygen Evolution Reaction (OER)

Recent progress in the activity improvement of anode catalysts for acidic electrochemical water splitting was largely achieved through empirical studies of iridium-based bimetallic oxides. However, practical, experimentally accessible, yet general predictors of catalytic OER activity are lacking. This study investigates iridium and iridium-nickel thin film model electrocatalysts for the OER and identifies a set of general ex situ properties that allow the reliable prediction of their OER activity. Well defined Ir-based catalysts of various chemical nature and composition were synthesized by magnetron sput-tering. Correlation of physico-chemical and electrocatalytic properties revealed two experimental OER activity descriptors that are able to predict trends in the OER activity of unknown Ir based catalyst systems. More specifically, our study demonstrates that the IrIII+ and OH-surface concentration of the oxide catalyst constitute closely correlated, and generally applicable OER activity predictors. Based on these, an experimental volcano relationship of Ir-based OER electrocatalysts is presented and discussed

Synthèse par pulvérisation cathodique et caractérisation d'électrolytes solides en couches minces pour piles à combustible à oxydes solides (SOFC) fonctionnant à température intermédiaire :

The major problem of Solid Oxide Fuel Cells (SOFC) is their operating temperature. One challenge is to decrease this temperature from 1000 to 700ÊC, 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 m). 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 700ÊC: 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.En vue de diminuer la température de fonctionnement de 1000 à 700°C des piles à combustible à oxydes solides (SOFC), il est nécessaire de réduire l'épaisseur du conducteur ionique pour limiter sa résistance. Dans ce contexte, la pulvérisation cathodique magnétron en condition réactive autorise la synthèse de revêtements dont l'épaisseur est compatible avec celle requise (~ 5-10 m). Après une description du dispositif expérimental et des techniques de caractérisation mise en ?uvres pour l'étude, nous présenterons les résultats concernant le matériau de référence des SOFC, la zircone stabilisée à l'yttrium (YSZ). Puis, nous exposerons les mesures sur deux candidats potentiels à son remplacement : la cérine gadoliniée (GDC) et le molybdate de lanthane (LAMOX). L'ensemble des mesures pour chaque composé est en accord avec la littérature. Enfin, une étude préliminaire est menée sur la synthèse d'un électrolyte bicouche de GDC/YSZ

A comparison of electrical properties of sputter-deposited electrolyte coatings dedicated to intermediate temperature solid oxide fuel cells

International audienceSolid electrolyte thin films of Yttria-Stabilised Zirconia (YSZ), Gadolinium-Doped Ceria (GDC) and Lanthanum-Molybdenum Oxide (LaMOx) are sputter-deposited or co-sputter-deposited on rotating substrates from metallic targets in reactive argon–oxygen mixtures. Their chemical and structural features are investigated by Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD) and their morphology is observed by Scanning Electron Microscopy (SEM) of brittle-fracture cross sections. Relationships are established with their electrical behaviour determined by means of Complex Impedance Spectroscopy (CIS). It is shown that the activation energy of the different electrolytes is consistent with the literature data after stabilisation of their microstructure by annealing around 800 °C

Synthèse par pulvérisation cathodique et caractérisation d'électrolytes solides en couches minces pour piles à combustible à oxydes solides (SOFC) fonctionnant à température intermédiaire

En vue de diminuer la température de fonctionnement de 1000 à 700C des piles à combustible à oxydes solides (SOFC), il est nécessaire de réduire l'épaisseur du conducteur ionique pour limiter sa résistance. Dans ce contexte, la pulvérisation cathodique magnétron en condition réactive autorise la synthèse de revêtements dont l'épaisseur est compatible avec celle requise (~ 5-10 m). Après une description du dispositif expérimental et des techniques de caractérisation mise en œuvres pour l'étude, nous présenterons les résultats concernant le matériau de référence des SOFC, la zircone stabilisée à l'yttrium (YSZ). Puis, nous exposerons les mesures sur deux candidats potentiels à son remplacement : la cérine gadoliniée (GDC) et le molybdate de lanthane (LAMOX). L'ensemble des mesures pour chaque composé est en accord avec la littérature. Enfin, une étude préliminaire est menée sur la synthèse d'un électrolyte bicouche de GDC/YSZ.The major problem of Solid Oxide Fuel Cells (SOFC) is their operating temperature. One challenge is to decrease this temperature from 1000 to 700C, 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 m). 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 700C: 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.NANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF

Surface treatment for fuel cell applications

International audienceNowadays, it is well known that Solid Oxide Fuel Cells (SOFC) lifetime improvement and cost reduction can be controlled by decreasing their operating temperature. In the SOFC technology, the delivered power is obtained after an oxy-reduction reaction governed by the Nernst and the Arrhenius laws. In order to obtain the same electric power while reducing the operating temperature, two methods are possible. The first one consists in developing a new material with better properties in terms of conductivity, catalytic efficiency and so on while the second one is to reduce the thickness of each part of the fuel cell.In this work, we present some recent results on anode and metal supported cells. Each element of the unit cell (anode, electrolyte and cathode) was deposited by thin technologies. After a short description of the experimental configuration, the structural, microstructural and morphological features of the cell were determined by XRD and SEM. The electrical properties were evaluated by using Electrochemical Impedance Spectroscopy (EIS) technique as a function of the temperature. Finally, the I-V-P curves of the complete cell were conducted at different temperatures

Thin films technologies for fuel cell applications

International audienceThin films technologies for fuel cell application

BITAVOX coatings obtained by reactive magnetron sputtering: Influence of thickness and composition

International audienceBITAVOX (Bi2TaxV1 − xO5.5) thin films with different thicknesses or compositions were deposited from Bi, Ta and V targets by reactive magnetron co-sputtering. As-deposited films are amorphous and have to be thermally treated at 700 °C for 2 h in order to crystallise. Increasing thickness leads to enhanced compressive stress. Moreover, porosity appears in the as-treated films. The electrochemical characterisation showed that the film resistance decreased with increasing thickness. Furthermore, the activation energies of the films are rather high in comparison with the bulk material, which can be attributed to a strong contribution of the inter-grain conduction to the total conductivity