The Disputation will be live streamed for everyone else.
The livestream will be activated 15 minutes before the Defense starts.
Trial lecture
May 08, 10:30 Auditorium 3, Chemistry Building
Trial lecture title: “Degradation of solid oxide devices (fuel cells, electrolysers and membranes). The key factors driving degradation and how they can be identified and monitored”
Conferral summary / Kreeringssammendrag
Doktoravhandlingen til Yizhou Shen viser at elektronoverføring spiller en viktig rolle for hastigheten til reaksjoner mellom oksygen og materialoverflater under høytemperatur-elektrokjemiske prosesser. Forskningen viser at tilgangen på elektroner, sammen med oksygenvakanser, kontrollerer reaksjonshastigheten. Inngående kunnskap om disse reaksjonene kan bidra til utviklingen av mer effektive brenselceller og oksygenmembraner.
Main research findings / Hovedfunn
The efficiency of clean energy technologies like solid oxide fuel cells depends on how quickly the positrode can exchange oxygen with air. Scientists have long focused on oxygen vacancies—sites where oxygen is incorporated into the material—as the key factor controlling this process.
However, this research reveals that the supply and movement of “electrons” is often the true bottleneck limiting the performance. When oxygen vacancies are abundant, boosting electron supply directly accelerates the reaction. Conversely, on surfaces rich in electrons, the reaction can be hindered by unfavourable electrostatic interactions. Additionally, water vapor can block these vacancies, further reducing performance.
Overall, this work shows that electron transfer is a dynamic process that often determines the rate-limiting step and is strongly influenced by the surface chemical environment. This insight provides new strategies for designing more efficient energy conversion materials by precisely tuning defects and electronic structure.
Candidate contact information
http://linkedin.com/in/yizhou-shen-879835134
E-mail: sensishen@gmail.com
Telephone: +47 92558529
Adjudication committee
Professor Stephen Skinner
Imperial College London, United Kingdom
Associate professor Astri Bjørnetun Haugen
Department of Energy Conversions and Storage, Technical University of Denmark
Professor Ola Nilsen
Department of Chemistry, University of Oslo, Norway
Chair of defence
Professor Unni Olsbye
Department of Chemistry, University of Oslo, Norway
Supervisors
Professor Reidar Haugsrud
Department of Chemistry, University of Oslo, Norway
Professor Truls Norby
Department of Chemistry, University of Oslo, Norway
Research Scientist Dr. Tor S. Bjørheim,
CoorsTek Membrane Sciences, Norway
Dr. Vincent Thoréton
CEA Grenoble, France