Recherche
Polybenzimidazole Membrane Design Principles for Vanadium Redox Flow Batteries
Energy storage technologies with long storage duration are essential to stabilize electricity grids with a high share of intermittent renewable power. In a redox flow battery, the electrochemical conversion unit, where the charging and discharging reaction takes place, is spatially separated from the energy storage medium. In the all-vanadium redox flow battery (VRFB), a sulfuric acid aqueous electrolyte with dissolved vanadium ions is used as the storage medium. Vanadium is present in 4 different oxidation states, the redox couple vanadium(II) and (III) on the negative side of the cell, and vanadium(IV) and (V) on the positive side. This allows the battery to be repeatedly charged and discharged. A separator or membrane is used between the negative and positive electrode, which should selectively conduct the ions of the supporting electrolyte and minimize the passage of vanadium ions. Fluorinated membranes, such as Nafion™, are often used for this key component, but these ionomers were not originally developed for this application and therefore have functional shortcomings. Furthermore, the production and use of fluorinated materials is to be severely restricted or even banned in Europe. Therefore, the development of hydrocarbon-based membranes for the VRFB is of great importance. The study reported here focuses on polybenzimidazole polymers and membranes, which could be a promising materials class for next generation flow batteries.
«Objectiver le débat sur l’énergie»
Le débat sur l'énergie a besoin de plus de faits et de moins d'intuition - c'est ce que plaident l'expert en énergies renouvelables Thomas J. Schmidt et le chercheur en énergie nucléaire Andreas Pautz.
Enabling the use of Thin Membranes in Water Electrolyzers using a Recombination Catalyst
The conversion efficiency for green hydrogen production in a polymer electrolyte water electrolyzer (PEWE) is strongly influenced by the ohmic cell resistance and therefore the thickness of the membrane used. The use of thin membranes (~50 micron or below) is limited by gas crossover of H2 and O2, which can lead to the formation of explosive gas mixtures. The incorporation of a recombination catalyst provides remedy and allows a more dynamic operating mode.
Mit Röntgenlicht zu besseren Antrieben
Um den Strassenverkehr der Schweiz zukunftsfähig zu machen, ist vor allem Forschung gefragt. In den Grossforschungsanlagen des PSI untersuchen Chemiker und Ingenieure, wie Antriebe effizienter und abgasärmer werden.
Ice in fuel cells imaged directly for the first time
Researchers from the Paul Scherrer Institute (PSI) have succeeded in imaging the distribution of frozen and liquid water in a hydrogen fuel cell directly for the first time. They applied a new imaging technique that uses successively two beams with different neutron energies to distinguish between areas with liquid water and those with ice extremely reliably. The method therefore opens up the prospect of studying one of the main problems of using fuel cells to power vehicles: ice can clog the pores in the fuel cells and affect their performance. The PSI scientists’ results will be published in the journal Physical Review Letters on 16 June 2014.
Zukünftige Computerchips mit "elektronischem Blutkreislauf"
Im Rahmen des Sinergia-Programms fördert der Schweizerische Nationalfonds das dreijährige Forschungsvorhaben REPCOOL. Unter der Leitung von IBM Research à Zürich arbeiten in diesem Projekt Wissenschaftler der ETH Zürich, des Paul Scherrer Instituts in Villigen und der Università della Svizzera italiana in Lugano gemeinsam an der Erforschung eines elektronischen Blutkreislaufs für zukünftige 3D-Computerchips. Vom menschlichen Gehirn inspiriert, entwickeln die Forscher ein Mikrokanalsystem mit einer elektrochemischen Flussbatterie, die 3D-Chipstapel gleichzeitig kühlen und mit Energie versorgen. Ultimatives Ziel ist die Entwicklung eines Supercomputers in PC-Grösse.Cette actualité n'existe qu'en allemand.
Green fuels for aviation
In a new initiative, PSI and Empa want to jointly develop a process for producing kerosene from renewable resources.
La Suisse en route vers le zéro net
Les institutions du Domaine des EPF mettent en commun leur expertise pour atteindre l’objectif zéro net.
Oxygen Evolution Reaction Activity and Underlying Mechanism of Perovskite Electrocatalysts at Different pH
PSI researchers have studied the how the electrolyte pH values influence the oxygen evolution reaction (OER) activity and stability of different promising perovskite oxide catalysts for application as anodic electrodes in alkaline water electrolyzers. The OER activity and stability decreased decreasing the electrolyte pH values. By combining electrochemical studies and operando X-ray absorption spectroscopy measurements, it has been suggested that different reaction mechanisms dominate in alkaline and near-neutral electrolyte pH region.
Publications 2009
Electrochemistry Laboratory (LEC)
Cinq fois moins de platine : grâce à un nouveau catalyseur aérogel, les piles à combustible pourraient devenir économiquement attrayantes
Les piles à combustible produisent de l’électricité à partir d’hydrogène et n’émettent que de l’eau, elles sont une alternative écologique pour la mobilité individuelle du futur. Depuis plus de 10 années, l’Institut Paul Scherrer (PSI) étudie et développe des piles à combustibles basse température à membrane polymère. Les premiers tests pratiques ont montré que ces piles à combustible peuvent être utilisées avec succès pour des voitures et des bus. Mais d’autres recherches restent nécessaires pour améliorer la longévité de cette technologie et la rendre économiquement viable. Une équipe internationale de chercheurs, à laquelle participe le PSI, a fabriqué un nanomatériau potentiellement capable d’améliorer la performance et la durabilité de ces piles à combustible à tout en réduisant les coûts.
Surface segregation acts as surface engineering for the oxygen evolution reaction on perovskite oxides in alkaline media
PSI researchers have studied the influence of surface segregation on the oxygen evolution reaction (OER) activity for the, La0.2Sr0.8CoO3-d (LSCO) perovskite, one of the most active perovskite towards the OER in alkaline electrolyte. It has been found that the higher the perovskite synthesis temperature the more strontium segregation occurs on the surface. However, the segregated strontium compounds are soluble in water and they are easily removed when the surface of the electrode is in contact with the electrolyte, leading to the exposure of cobalt enriched layers very active for the OER.