SSRL Discoveries Point to Better Batteries
SSRL Science
Summary - October 2012
Energy storage materials, such as batteries, are of increasing importance in
the modern world. They support the storage and distribution of electricity
generated by different mechanisms, enabling the use of green power sources when
the resource itself is unavailable (for example, solar energy at night or wind
energy on a calm day). Such devices also provide energy portability for
consumer electronics and zero-emission options for transportation, in either
hybrid or fully-electric vehicles. Many impressive battery technologies exist
today, but the understanding of their operation is somewhat limited, which
makes it very challenging to improve their performance. For example, battery
microstructure - specifically, the assembly of particles into electrode systems
- plays a critical role in determining the efficacy of the device, but
available inspection technologies have limited characterization efforts to
cells that have been depackaged or otherwise prepared for study. Such
preparations present a practical limit to understanding how the battery works
under realistic conditions. They also prohibit real-world studies of changes in
microstructure - the very mechanisms that may lead to failure - as a function
of operation.
Researchers at SSRL, General Motors, Imperial College London, National Taiwan
University, and elsewhere have recently begun experimenting with 3-D
transmission X-ray microscopy (TXM), in order to gain new insight into the
microstructure of battery electrodes. Researchers from University College
London, Imperial College London, the University of Manchester and Xradia, Inc.,
conducted a comprehensive multi-length scale investigation which enabled the
introduction of guidelines for future battery microstructure investigations. )
They extended laboratory micron-scale imaging to both laboratory and
synchrotron nano-imaging in order to characterize the types of information
obtained at each length scale. The study found that laboratory micro-imaging
reveals the bulk pore and transport pathways, while laboratory nano-scale TXM
delivers the precise pore pathways (for example, tortuosity) and particle
shapes. Synchrotron nano-scale TXM performed at SSRL Beam Line 6-2 clearly
revealed intra-particle imperfections which have only been detected in the past
on specially prepared samples imaged with TEM.
Using the power of both laboratory- and synchrotron-TXM, the precise 3-D
information about battery micro- and nano-structures will enable a new
generation of electrochemical research. The flexibility of the non-destructive
approach is already enabling novel functional studies of electrode operation,
and the recent work at SSRL will help guide this research to optimized results.
Primary Citation
P. R. Shearing, N. P. Brandon, J. Gelb, R. Bradley, P. J. Withers, A. J. Marquis, S. Cooper and S. J. Harris, "Multi Length Scale Microstructural Investigations of a Commercially Available Li-Ion Battery Electrode", Journal of The Electrochemical Society, 159 (7) A1023-A1027 (2012) [DOI: 10.1149/2.053207jes]Related Links
Contact
Jeff Gelb, Xradia
