CAREER: Probing Oxygen-Mediated Electrochemical Processes of Oxides at High Spatial and Temporal Resolution

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NON-TECHNICAL DESCRIPTION: Solid oxide fuel cells - devices that produces electricity directly from oxidizing a fuel - are considered routes for clean and efficient energy conversion. Since the performance of these devices is largely determined by the kinetics of the oxygen-based electrochemical reaction occurring at the air electrode, intense efforts have been made to improve the electrode performance and better understand it on a fundamental level. While each elementary process of the reaction is intrinsically a nanoscale phenomenon dictated by local material properties and geometry, the electrochemical properties have been mostly analyzed through bulk (volume-averaged) measurements. To obtain a breakthrough in electrode design, a more thorough understanding of the process at the nanoscale is needed. This project aims for new insights about the electrochemical reactions through in situ nanoscale observations, which is enabled by a novel scanning probe microscopy type instrument. This project is training undergraduate and graduate researchers (including underrepresented minority students) for their future employment in the energy technology sector. TECHNICAL DETAILS: The performance of solid oxide fuel cells and electrolyzers are largely affected by the kinetics of oxygen reduction/evolution reactions (ORR/OER). While intense efforts have been made to understand the underpinning mechanisms of the reactions, nanoscale processes during the reaction are largely unknown. This project aims to advance the understanding of ORR/OER processes through in situ nanoscale observations by leveraging a novel scanning probe-based setup with a microscale heater. There are three significant aspects of this research: 1) demonstrating a new high temperature scanning probe-based approach for in situ nanoscale characterizations of electrochemical surface reaction and charge transport kinetics under operating oxygen activities; 2) pioneering a novel time-resolved nanoscale characterization of thermally-activated processes; 3) providing deeper insight regarding the ORR/OER and related charge transport at the nanoscale. The project provides extensive research opportunities for graduate and undergraduate students, enhances curricula by incorporating research into seminars and courses, and promotes effective education for K-12 students from the local and surrounding rural communities in the Central Valley through the on-campus Engineering Service Learning.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.