BEGIN:VCALENDAR VERSION:2.0 PRODID:https://murmitoyen.com/events/vanille/udem/ X-WR-TIMEZONE:America/Montreal BEGIN:VEVENT UID:69da55b2b5708 DTSTAMP:20260411T100746 DTSTART:20180827T113000 SEQUENCE:0 TRANSP:OPAQUE DTEND:20180827T123000 URL:https://murmitoyen.com/events/vanille/udem/detail/830222-the-discovery- of-the-proton-polaron-artur-braun-empa-suisse LOCATION:Université de Montréal - Pavillon J.-Armand-Bombardier\, 5155\, chemin de la rampe \, Montréal\, QC\, Canada\, H3T 2B2 SUMMARY:The discovery of the proton polaron - Artur Braun (Empa\, Suisse) DESCRIPTION:The discovery of the proton polaronArtur BraunLaboratory for Hi gh Performance CeramicsEmpa. Swiss Federal Laboratories for Materials Scie nce and Technology High Performance CeramicsDübendorf\, Switzerland Abstr act: In electrochemical energy storage and conversion\, electrodes and ele ctrolytes are the key components of batteries\, fuel cells and capacitors. Electrons and ions are the relevant electric charge carriers. The key pla yer in technology for the hydrogen economy is the proton - an elusive char ge carrier which cannot be so easy detected [1]. Ceramic proton conductors can be used as electrolyte membranes in solid state devices. Smart defect engineering makes that oxygen vacancies can be filled with oxygen ions fr om ambient vapor water molecules. The protons from the water molecule form intermediate OH bonds with proximate oxygen ions. Upon thermal activation \, the OH bonds melt and the proton be-comes liberated as positive charge carrier. The transport properties of the yttrium doped barium cerate and b arium zirconate electrolytes were investigated by thermodynamic parameteri zation of their structure with temperature 273 K - 773 K and pressure 0 - 6 GPa. The proton conductivity activation energy decreases linear with inc reasing lattice spacing\, suggesting that epitaxial strained films should be promising future electrolyte membranes. The Raman modes increase with i ncreasing pressure and get a slightly higher 'pitch' upon protonation. The OH bond breaking occurs at a characteristic temperature range which is ac companied by the onset of a lateral proton diffusivity which accounts for the macroscopic conductivity as measured with electroanalytical methods. A t the microscopic scale\, ambient pressure XPS and quasi elastic neutron s cattering which were carried out operando parallel on the same samples wit h impedance spectroscopy\, confirm that it is exactly this proton phonon c oupling which switches the proton conductivity on. The quantitative analys is of the proton jumping frequencies showed that the Ce-O stretching mode is the effective propeller for the proton at work. Moreover\, the temperat ure dependence of the proton jump frequency follows exactly the mathematic al model for a Holstein polaron\, rendering the proton conductivity proces s in ceramic proton conductors a genuine proton polaron [2]. [1] Q. Chen\, A. Braun\, MRS Energy & Sustainability\, 4\, E14 (2017).[2] A. Braun\, Q. Chen\, Nature Communications\, 8\, 15830 (2017). Research done in collabo ration with Qianli Chen (University of Michigan – Shanghai Jiao Tong Uni versity Joint Institute\, Shanghai\, China) Web site of Dr. Braun's resear ch group. Cette conférence est présentée par le RQMP Versant Nord du  Département de physique de l'Université de Montréal et de Génie ph ysique de la Polytechnique. END:VEVENT BEGIN:VTIMEZONE TZID:America/Montreal X-LIC-LOCATION:America/Montreal END:VTIMEZONE END:VCALENDAR