Invited Talks: Transition Metal Oxides - University Blog Service - The ...

The John B. Goodenough Symposium in Materials Science & Engineering–
In Honor of His 90 th Birthday
The University of Texas at Austin, Austin, Texas
October 26-27, 2012
Understanding Interfacial Reactivity of Silicon Nanostructures
Sankaran Murugesan ± , Kjell Schroder*, Justin T. Harris + , Lauren Webb* ,± , Brian A. Korgel* ,+ and Keith J. Stevenson* , ±
± Department of Chemistry & Biochemistry, + Department of Chemical Engineering, *Materials Science and
Engineering Program, The University of Texas at Austin
Abstract Body in Space Below:
(Please use single space, Times New Roman or similar font, size 12, and limit to 250 Words. Please DO NOT exceed the space
below.)
In recent years Si has drawn considerable interest as an anode material for Lithium ion batteries
(LIB) due to its high gravimetric and volumetric energy density. Si can react with Li and form an alloy of
Li 15 Si 4 , corresponding to a very high charge storage capacity of 3579 mAh/g that is approximately 10
times higher in gravimetric capacity than graphite. However, Si-based anodes face several challenges.
First, crystalline Si anodes undergo a 400% volume expansion during the lithiation process. Typically
large irreversible capacity losses are observed during lithiation/delithiation since volume expansion and
contraction cause pulverization of the Si and loss of electrical contact with the current collector. Secondly,
the electrochemical alloying potential of Si is above the solvent reduction level, which leads to the
formation of a solid electrolyte interface (SEI). These fundamental processes are investigated through high
resolution spectroscopic techniques. What effects volumetric expansion/contraction processes in Si and
how can they be controlled What factors govern charge transfer kinetics and how can charge transfer
resistance be controlled What influence do morphology and surface chemistry have on reversibility and
charge storage capacity What role does SEI play in the charge transfer process between the electrolyte
and electrode