Seminar & Colloquium
[세미나: 7월 5일(금), 오전 10시 30분] Dr. Jae Jin Kim, Argonne National Laboratory
Title
Advanced characterization of energy materials by using model systems
Speaker
Dr. Jae Jin Kim, Materials Scientist, Chemical Sciences and Engineering Division, Argonne National Laboratory
* Education
- Sep. 2009 - Jun. 2015 Ph.D. in Materials Science and Engineering, Massachusetts Institute of Technology Cambridge, MA
Advisor: Prof. Harry L. Tuller
Thesis title: “Defect Equilibria and Electrode Kinetics in PrxCe1-xO2-δ Mixed Conducting Thin Films: An in-situ Optical and Electrochemical Investigation”
- Sep. 2006 - Aug. 2008 M.S. in Materials Science and Engineering, Seoul National University Seoul, South Korea
Advisor: Prof. Soo Young Park
Thesis title: “Synthesis and Dendritic Effects of Novel Silicon-Containing TrisCyclometalated Homoleptic Iridium (III) Complexes”
- Mar. 2000 - Aug. 2006 B.S. Materials Science and Engineering, Seoul National University Seoul, South Korea(Cum Laude)
* Professional Experience
- Dec. 2023 - present Materials Scientist, Argonne National Laboratory
- Apr. 2019 - Nov. 2023 Assistant Materials Scientist, Argonne National Laboratory
- Aug. 2015 - Apr. 2019 Postdoctoral Researcher, Argonne National Laboratory
- Sep. 2009 - Aug. 2015 Research Assistant, Massachusetts Institute of Technology
- Sep. 2008- Jun. 2009 Staff Researcher, Seoul National University
- Sep. 2006 - Aug. 2008 Research Assistant, Seoul National University
| Date | Friday, July 5th , 2024
| Time | 10:30 ~
| Venue | 33동 125호(WCU 다목적실)
[Abstract]
Understanding and controlling complex materials behavior, i.e. structure-property-performance
relations, which can be obtained with fundamental observation from advanced characterization
techniques at device operating conditions, is critical to design and development of high performing
energy materials. In this talk, I will discuss some of my research activities that I combined multi-
scale model systems with in situ, in operando materials characterization and computational
models for this purpose. First, the effort for developing a reliable investigation technique for oxide
thin films to improve the fundamental understanding of their defect chemistry and surface
exchange kinetics will be discussed. These properties are critical in optimizing performance of
electrochemical energy conversion systems such as solid oxide fuel/electrolysis cells
(SOFCs/SOECs), metal-air batteries and water-splitting devices. Conventional characterization
methods are often severely limited when applied to thin films due to their inherent high aspect
ratio and low mass. In order to overcome the related issues, a new characterization setup with
simultaneously utilizing optical transmission and impedance measurements was developed. This
novel measurement technique allowed one to investigate the thermodynamics and reaction
kinetics of oxide thin films, which often differ from those of bulk materials. In addition, the isolation
of variables such as metal contacts, film strain and thermal history can be achieved. Next,
investigation of the surface electrochemical activity of Mg ions in Mg-ion battery cathode materials,
by using a spinel-structured manganese oxide thin-film model system and in situ X-ray scattering,
will be discussed. In combination with post-mortem microscopy analysis, magnesium insertion
was found to be more favorable than subsequent extraction near the surface of the MgxMn2O4
film, resulting in overmagnesiation, and eventually amorphization of the surface. This structural
irreversibility and high overpotential required for Mg extraction could explain significant voltage
hysteresis and Mg surface enrichment previously observed in bulk cathodes. Density functional
theory calculations suggested that the tendency for the Mg surface enrichment could be
associated with Mg diffusion kinetics, which varies with the strain state evolved due to constrained
film volume change during Mg insertion and extraction. Particularly, out-of-plane Mg migration
was predicted to be favorable in the tensile strain rather than in the compressive case.
| Host | 한정우 교수(02-880-1608)