Abstract
For energy-related materials, the understanding of property-structure relationship is based on the knowledge of their structure, interfaces and phase evolution. Advanced (scanning) transmission electron microscopy ((S)TEM) techniques have been applied to investigate the structure as well as their functions of the energy-related materials, with the help of combined electrochemical and theoretical approaches. In the first part of this talk, I will discuss my recent work on TEM characterization of the conversion oxide compounds for lithium/sodium ion batteries.  While our ex situ TEM study reveal the structural change in the real cell probe local structural and chemical information at a spatial resolution of nanoscale., in situ TEM study can help us to understand the process of lithiation/sodiation. In the cases of rocksalt-structure oxide(NiO)[1-2] and spinel oxides(Fe3O4 and Co3O4)[3-4] compounds, we have investigated the dynamical process of the redox reaction in real time. The role of reaction pathways is highlighted which is supposed to affect the batteries’ kinetic properties. In the second part of the talk, I will discuss the strain coupling of highly uniform PtPb/Pt core/shell nanoplates [5], which may help to optimize the Pt-O bond strength and therefore boost their activity and stability for oxygen reduction reaction (ORR).
Reference:
[1] Transitions from Near-Surface to Interior Redox upon Lithiation in Conversion Electrode Materials, Kai He, et. al, Nano Letters, 15, 1444, (2015)
[2] Sodiation Kinetics of Metal Oxide Conversion Electrodes: a Comparative Study with Lithiation, Kai He, et. al, Nano Letters, 15, 5755, (2015)
[3] Visualizing Non-Equilibrium Lithiation of Spinel Oxide via In Situ Transmission Electron Microscopy, Kai He, et al., Nature Communications, 7:11441 doi: 10.1038/ncomms11441, (2016)
[4] Kinetic Phase Evolution of Spinel Cobalt Oxide during Lithiation, Jing Li, et al., ACS Nano,  10, 9577-9585, (2016)
[5] Biaxially strained PtPb/Pt core/shell nanoplate boosts oxygen reduction catalysis, Bu et al., Science, 354, 1410-1414(2016)

Brief bio: 
Dr. Dong Su did his undergraduate work(1998) at Nanjing University and graduate work(2004) at Nanjing University and thesis at Institute of Physics, CAS, followed by postdoc sojourns at EPFL(Switzerland), Univ. of Illinois at Urbana-Champaign and Arizona State University (US). Since 2008, He has been a  Scientific Staff at the Center for Functional Nanomaterials in Brookhaven National Laboratory. Dr. Su has published ~210 papers ( ~9,500 citations and h index=41, according to Google Scholar) and presented ~20 invited talks at conferences or academic institutions. His current research interests include energy related materials: including nanocrystals for catalysis and oxide compounds for rechargeable batteries, and  in situ transmission electron microscopy.