When 3:30 PM - 5:00 PM Mar 23, 2012
Where 1670 CSE Building
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In-Situ TEM Observations of Electrochemical Reactions of Individual Nanowire or Nanoparticle Electrodes in Lithium Ion Batteries

Jianyu Huang
Center for Integrated Nanotechnologies, Sandia National Laboratories

Recently, we created the first Li-ion electrochemical cell (a nano-battery) inside a transmission electron microscope (TEM) and observed, in real time with atomic scale resolution, the battery charging and discharging processes. This experiment opened the door for a suite of experimental studies involving in-situ TEM characterization of Li-ion battery (LIB) materials.  In this presentation, I’ll first review our latest progress of using the nano-battery setup inside the TEM to reveal the intrinsic electrochemistry of several high energy density anode materials such as SnO2, ZnO, Si, Ge, Al nanowires, Si, Ge, Sn nanoparticles, carbon nanotubes, and graphene. Several electrochemical mechanisms were observed and characterized in real-time, including lithiation induced stress, volume changes, phase transformations, pulverization, cracking, embrittlement, and mechanical failure in anode materials. These results indicate the strong material, size and crystallographic orientation dependent electrochemical behavior and degradation mechanisms that occur in LIB anodes. In the future, we will need further advancements in in-situ characterization for understanding important processes in LIBs.  For example, liquid cells are required in order to examine the electrochemical reactions between battery materials and the standard battery electrolytes, which are ethylene carbonate-based.  Furthermore, in-situ studies need to be correlated with electrochemical studies performed on bulk electrodes.  I will present a comparison between our in-situ results and electrochemical studies on conventional battery electrodes and highlight how in-situ studies can have important impact on the design of LIBs.  Finally I will discuss outstanding challenging issues and opportunities in the field of LIB research.

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