Abstracts Book - IMRC 2018

• SD5-O006 Invited Talk
IN SITU STUDIES OF THE INTERCALATION OF GRAPHITE
B. C. Regan 1,2
1 University of California, Los Angeles, California NanoSystems Institute, United States.
2 University of California, Los Angeles, Department of Physics and Astronomy, United States.
The ubiquitous lithium-ion battery features a graphite anode. Charging and
discharging the battery moves lithium into and out of the graphite via a process
called intercalation. In thermal equilibrium, the lithium carbide compounds
formed by intercalating graphite are known to be ordered, or staged, with an
integer numbers of graphene layers (the stage number) separating the
intercalant lithium layers. Surprisingly, at stoichiometries less lithium-rich than
the fully charged, stage-1 compound LiC 6 , the three-dimensional structures of
these lithium carbide compounds are not well-understood, even in the idealized
case of a perfectly crystalline graphite host at thermal equilibrium. Moreover,
even less is known about the mechanics of the transitions between
stoichiometries with different stage numbers. To address these problems, we
have been applying in situ electron and optical microscopy to the study of
electrochemical intercalation in single microcrystals of high-quality, natural
graphite. We find that defects play a large role in regulating transport, and that
a pristine crystalline host is radically and irreversibly altered by its first lithiation.
Acknowledgment:
This work was supported by STROBE, a National Science Foundation (NSF)
Science and Technology Center (STC) under Grant No. DMR-1548924, and by
NSF Grant No. DMR-1611036.
Keywords: in situ microscopy, lithium intercalation, battery
Presenting authors email: regan@physics.ucla.edu