ChEMS Seminar: Scanning/Transmission Electron Microscopy and Spectroscopy beyond Aberration Correction - In-situ Microscopy for Watching while It Happens

Engineering Tower 652
Chongmin Wang

Environmental Molecular Sciences Laboratory
Pacific Northwest National Laboratory, Richland, WA


Abstract: Over the last decades, we have witnessed tremendous progress in the development of aberration-corrected transmission electron microscopy and scanning transmission electron microscopy. As a result, imaging of materials at atomic scale and spectroscopying at sub-nanometer scale have become routine practice. The questions now are how do we extend the microscopy and spectroscopy methodologies to analyze materials at or near realistic condition, such as real time observation of the catalytic process, oxidation and reduction; bio-tissue in a liquid cell; defects generation and interaction under deformation conditions; mass transport and microstructural evolution; and charge and ion transport process.  Approaches that are employed to provide in-situ observation of chemical reactions and microstructural evolution include, but are not limited to, the use of differential pumping technologies, the modification of sample holders to enable the application of an external stimulus such as an electromagnetic field or stress, using thin membrane closed cells for experiments involving liquids or gases, and use of liquid with low-vapor pressure. In view of these developments, I will, for this presentatio,n focus on in-situ techniques developed for probing into the structural and chemical information of energy storage materials, highlighting direct observation of structural evolution, phase transformation and their correlation with mass, charge and electron transport, providing insights on active materials failure during the cyclic charging and discharging of a battery. In perspective, challenges and possible direction for further development of the in-situ TEM imaging and spectroscopic methods for both functional and structural materials and other fields will be discussed.

Bio: Chongmin Wang received his bachelor's and master's degrees in physics from Lanzhou University, China, and a doctorate in materials science and engineering from the University of Leeds, UK. He worked at Max-Planck Institute for Metal Research in Stuttgart, Germany, as an Alexander von Humboldt Research Fellow; National Institute for Materials Science in Japan; and Lehigh University,where he focused on atomic level study of grain boundary structure and chemistry using S/TEM. He is currently a chief scientist at Pacific Northwest National Laboratory, and his research interests include the state-of-the-art S/TEM imaging and spectroscopy and their application to materials characterization, especially in situ and operando S/TEM techniques for energy materials application. He is one of the pioneers on in-situ TEM technique for rechargeable battery research, which has earned him prestigious honors, including the 2012 Microscopy Today Innovation Award, 2016 MRS Innovation in Materials Characterization Award (shared with Frances Ross of IBM T. J. Waterson Research Center and Niels de Jonge of Leibniz Institute for New Materials, Germany); 2015 Journal of Materials Research (JMR) Paper of the Year Award; 2017 PNNL Laboratory Director’s Award for Exceptional Scientific Achievement, 2017 and 2013 PNNL Pathway to Excellence Award. He also is the recipient of the R&D100 Award, Rowland Snow Award from the American Ceramic Society, Outstanding Invention Award from the Japanese Science and Education Committee and the PNNL Exceptional Contribution Award. Wang has published 360 journal papers, with a total citation of 16,000 and an H-index of 65, and he has delivered 60 invited talks. He currently serves as the principal editor of the Journal of Materials Research and is a fellow of the Materials Research Society.  

Host: Julie Schoenung