The use of high resolution X-ray CT has provided here the first quantitative microstructural, 3D reconstruction of a Li ion battery electrode.
Several geometrical parameters were extracted, including porosity, tortuosity, surface area and pore and particle size distribution. (In this work the spatial resolution was limited to about 480 nm, the voxel size.) The availability of highly detailed 3D tomography data for lithium ion batteries provides opportunities to test theoretically and empirically derived relationships, such as the Bruggeman relationship; and to learn how changes in electrode architecture correlate to changes in cell performance that reflect battery aging, degradation, failure, and general durability. The video shows a 3D portion of the graphite electrode. Total reconstructed volume 43 x 348 x 478 μm, encompassing the full electrode thickness. We expect that by analyzing changes in the microstructure we will have a better understanding of the factors that control battery life.
X-ray nano-scale tomography of graphite electrode. Total reconstructed volume is 43 x 348 x 478 μm, encompassing the full electrode thickness, with 480nm voxel size. Porosity is measured to be 15%. Actual porosity could be larger because of the presence of pores too small to be detected with our 480 nm spatial resolution
P.R. Shearing, L. E. Howard, P.S. Jørgensen, N.P. Brandon, and S. J. Harris, “Characterization of the 3-dimensional microstructure of a graphite negative electrode from a Li-ion battery,” Electrochemisstry Communications 12:374 (2010)
Paul Shearing acknowledges support from the UK EPSRC Supergen Programme. Peter Jørgensen acknowledges financial support from The Danish Council for Strategic Research, via the SERC project , contract no. 2104-06-0011