MSE PhD Final Defense of Boshan Mo

TITLE: ROLE OF MIXED IONIC AND ELECTRONIC TRANSPORT ON ELECTROCATALYTIC ACTIVITY OF INFILTRATED NANOPARTICLES IN SOLID OXIDE FUEL CELL CERMET ELECTRODES

ABSTRACT: The infiltration of nanoparticle electrocatalysts into solid oxide fuel cell (SOFC) electrodes has been proven to produce a high density of electrochemically active sites, and reduce charge transfer polarization losses for SOFC electrodes. This is crucial for intermediate temperature operation, as these losses increase greatly at lower temperatures. Nickel-yttria stabilized zirconia (Ni-YSZ) cermets are low-cost, and exhibit excellent stability, but their main disadvantage stems from nickel coarsening and performance loss over their operational lifetimes. Infiltration of electrocatalyst nanoparticles has been shown to mitigate nickel coarsening and the consequent anode degradation. In this study, the effects of these infiltrants are observed in a standard Ni-YSZ electrode. In addition to nickel, mixed ionic and electronic conducting (MIEC) phases were infiltrated into Ni-YSZ scaffolds and their performances were characterized using electrochemical impedance spectroscopy (EIS). The use of MIEC phases present in the ionic scaffold with and without infiltration was also measured. Cross-sectional microscopy of fractured cells was used to compare electrode microstructure and particle statistics. A model is proposed for how the nanoparticle electrocatalysts improve the anode performance under the effects of different temperature and humidity levels.

COMMITTEE: ADVISORProfessor Srikanth Gopalan, MSE, ME; Professor Uday Pal, MSE, ME; Professor Soumendra Basu, MSE, ME; Professor Emily Ryan, MSE, ME; CHAIR: David Bishop, MSE, ECE, BME, Physics

When 2:00 pm to 3:00 pm on Friday, November 20, 2020
Location ZOOM