Analysis of Void Volume in Composite Electrode of All-solid-state Lithium-ion Battery Employing FIB-SEM and Union Operation Image Processing

Yuta Yamamoto , Yasutoshi Iriyama, and Shunsuke Muto

We had proposed an image-processing scheme using union operation suitable for extracting target features with hierarchical dimensions from the original data, and applied it to void analysis in a composite electrode of an all-solid-state lithium ion battery (LIB). Void analysis is very important in developing better composite electrodes for all-solid-state LIBs because internal voids should increase the interfacial resistance. Film formation of electrode-solid electrolyte composites by the aerosol deposition (AD) method has attracted attention as an effective way to improve the density of the composite electrodes. In the present study, three-dimensional (3D) structure of the composite electrode, which was modified by the AD process to reduce the internal void volume, was investigated using FIB-SEM system. The void volume in the composite electrode was then analyzed by an image-processing method based on the union operation.

How Amira-Avizo Software is used

The software, Avizo was used for 3D image reconstruction, image processing and volume rendering. All the SEM images subsequently obtained was aligned in position with the substrates and vacuum spaces trimmed away, and then three different objective filters was separately applied: a median blur filter to filter out relatively larger voids, a morphological opening filter for small dot-shaped voids and a morphological closing filter for small voids with concave contrasts. The processed three filtered image data were individually subtracted from the original volume data with additional structures other than voids carefully ruled out by setting appropriate intensity thresholds. The resultant three volume data were finally unified by the union operation.