In situ tracking of microstructural evolution along with quantitative analysis in three dimensions (3D) of an electrode inside a battery as it cycles is a much-desired goal under intensive investigations.  We observed and quantitatively analyzed in situ nanometer scale 3D microstructural evolutions of a lithium-ion battery's Sn electrode during cycling. Severe microstructural changes occur during the first delithiation and subsequent second lithiation, after which the particles reach structural equilibrium with no further significant morphological changes. This reveals that initial delithiation and subsequent lithiation play a dominant role in the structural instability that yields mechanical degradation. Curvature analysis and finite element modelling elucidate that concave features of the particles develop a wider stress distribution which is higher than the materials yield stress, introducing a way of engineering the processing of the electrode materials for better performance.  This in situ 3D quantitative analysis and visualization of nanometer scale microstructural evolution by synchrotron x-ray nano-tomography will contribute greatly to understanding energy materials and improving of synthetic processing the materials.

X-ray nano-imaging application on energy materials

248th National Meeting (2014)

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