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Lecture

Microfabrication of model Solid Oxide Fuel Cells for synchrotron-based operando studies

Friday (26.06.2020)
12:10 - 12:30 Room 1
Part of:


The MIEC Sr(Ti,Fe)O3-d (STF) gained much attention as new electrode material for its capability of working at intermediate temperatures both as cathode and anode by tuning its stoichiometry [3, 4]. Ni-doped STF (STFN) exsolves Fe-Ni nanoparticles (NPs) in a reducing atmosphere. NP exsolution boosts the performance of these IT-SOFC anodes by enhancing the H2 dissociative adsorption, reducing the anode polarization resistance and improving C tolerance. The underlying mechanisms and the reversibility of NP exsolution is a heavily debated topic, but if understood and controlled, it could be disruptive for SOFC technology. For this work, in order to understand the exsolution process and gain device-level insights at the gas/solid interface, model SOFCs suitable for synchrotron operando ambient pressure X-ray photoelectron spectroscopy / electron-yield absorption spectroscopies (AP-XPS/XAS) and electrochemical impedance spectroscopy (EIS) at high temperature in oxidizing or reducing atmospheres were fabricated using various microfabrication techniques (Fig.1) [7]. These YSZ-electrolyte supported half-cells have 200 nm of non-stoichiometric STFN (or STF for reference) as working electrode deposited by pulsed laser deposition PLD, onto photolithographed Pt current collectors and a porous Pt counter electrode deposited by reactive sputtering. Here we present details of the cells fabrication process and some exemplary synchrotron based results. We discuss how dedicated synchrotron-based operando studies on model devices are extremely useful to study energy conversion processes that in turn, guide an application-oriented material (or device or component) optimization. Protocols for quality control are also critical upon each fabrication step of model devices to conduct experiments that result meaningful for the application.

Speaker:
Dr.-Ing. Catalina Jiménez
Helmholtz-Zentrum Berlin für Materialien und Energie

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