The video shows a rendering of a reconstruction (obtained by focused ion beam tomography) of the microscopic structure of a lithium iron phosphate (LiFePO4) cathode. The electrode was obtained from a commercial 18650 high-power LiFePO4/graphite cell. The LiFePO4 (shown in green in the animation) stores the lithium in the discharged state of the cell. It consists of very small primary particle which form larger spherical agglomerates of vaying size and porosity. By using such a dual-scale structure, the the diffusion paths within the particle are short, a very high active surface area is achieved and enough large pores are provided for transport within the liquid electrolyte. In order to ensure also a good electronic transport through the electrode structure, carbon fibers are added, which provide a good conductivity and an excellent percolation, even with a very low occupied volume fraction.
More details about this specific reconstruction can be found in my publication listed as reference  at the publications page.