In situ optical observations of particle motion in alloy negative electrodes for Li-ion batteries

Direct observation of the particles of active material as they react in situ is necessary to build an understanding of the interaction mechanisms present when large volume-change active materials are employed in composite electrodes. In situ optical observations of a-Si0.64Sn0.36 composite electrodes show dramatic interparticle movement; particles from below the electrode surface are pushed up, particles above the electrode surface shift downward, particles crash and overlap, particles become inactive, and some particles move so far that they become detached from the electrode. (C) 2006 The Electrochemical Society.