Materials for Energy
Presentation
The research carried out on the Materials for Energy platform are focussed on the research and characterisation of materials for Solid Oxide Fuel Cells, SOFC and high temperature electrolysers. These devices display good conversion, but their operating temperatures remain high, generally higher than 700°C. One of the objectives is to decrease the operating temperature through the research and characterisation of new electrolyte and electrode materials. These devices, fed on one side with air and on the other side with hydrogen, must be tight. The research of sealing glasses is also a key point of the activities.
There are several rooms on the platform, one laboratory dedicated to synthesis, one to the ceramics elaboration and another one to the electrochemical characterisations (in temperature, under atmospheres). A virtual visit of these rooms can be found on the Comasys project website, pillar 3 (https://comasys.univ-lille.fr/).
The technical platform is open to the researchers of the laboratory and it offers services or collaborations to academic or industrial laboratories.
The operating principle of a SOFC is based on oxide ions conductive ceramic which must be the thinnest as possible, on which are deposited electrode materials, that have to be porous to allow oxygen diffusion on one side and hydrogen diffusion on the other side. In SOFC mode, the chemical potential difference between an oxygen rich (air) environment and an oxygen poor one (hydrogen), induces natural migration from the rich to the poor side. Oxygen molecules are dissociated into oxide ions at the cathode, which migrate to the anode and react with hydrogen to form water, which induced the production of electricity. SOECs are based upon the reverse mode. Applying an electrical current allows the dissociation of water into hydrogen and oxide ions, which migrate to the anode to form dioxygen. Whereas the electrolyte has to be a pure oxide ion conductor, dense and the thinnest as possible, the electrode materials have to be mixed ionic electronic conductors and porous to allow gas diffusion to the reaction point.
The extensive study of electrode materials is performed by impedance spectroscopy. The analysis of impedance spectra measured under air or under various oxygen partial pressures allow to understand the limiting steps in the oxygen reduction reaction and provides keys to improve materials performances.
(PhD Fatima-Ezzahra EL BASSIRI, 25th January 2024)
Equipments
The platform Materials for Energy is equipped with a Spark Plasma Sintering device. By passing a high-intensity electric current through a graphite mould, the device allows the quick densification of ceramics in a few minutes against several hours for conventional sintering, allowing a limited grains growth (consolidation of nanometric powder, densification of refractory compounds, oxides, carbides, nitrides, borides, …). In short processing times the process is capable of producing high-strength, low-porosity components.
Caracteristics:
Maximal temperature: 2200°C
Maximal strength: 60 kN
Heating rate up to 2000°C/min
Reactive atmosphere: primary vacuum, secondary vacuum, argon or nitrogen partial pressure pression.
Location
Institut Chevreul, Cité Scientifique, Villeneuve d’Ascq
Contacts
The equipment of the plateau
Synthesis | balances (Sartorius, Kern440-45), Hot plates (VWR VMS-C7, IKA RH Digital, Fisher Brand, Velp Scientifica), Ultrasonic bath |
Synthesis, Sintering | Furnaces (Nabertherm 1750°C, Nabertherm 1100°C, 2 Nabertherm 1200°C), Spark Plasma Sintering (Suga Co Ltd – Sugaseisakusho kk) |
Shaping | Uniaxial press (Specac), isostatic press 1800 bar (NovaSwiss), polisher (Struers tegramin-20), diamond saw (Mecatome T180), Planetary mill (Fritsch), three-roll mill (Exakt), roller mixer (Stuart SRT9D), screen printer (Dek 248), spin coater (Polos), Gold evaporator, Drying oven (Venti-Line) |
Transport properties characterizations | isotopic exchange bench |
Electronical characterizations | 2 test benches (Fiaxell), 2 hydrogen generators (Parker MDS Industrie), 2 Solartron 1255, 2 Solartron 1260, Solartron 1280, booster Solartron 20A, Biologic SP150, Biologic SP300, Booster Biologic 10A |
Analysis | micro-GC (Agilent) |