Simulated annealing reconstruction and characterization of the three-dimensional microstructure of a LiCoO2 Lithium-ion battery cathode

•Simulated annealing approach is adapted for 3D reconstruction of LiCoO2 cathode.•Real size distribution of LiCoO2 particles is applied in reconstruction process.•Reconstructed cathode accords with real one at important statistical properties.•Effective electrode-characterization approaches have been established.•Extensive characterization gives important structural properties, say, tortuosity.

We adapt the simulated annealing approach for reconstruction of the 3D microstructure of a LiCoO2 cathode from a commercial Li-ion battery. The real size distribution curve of LiCoO2 particles is applied to regulate the reconstruction process. By discretizing a 40 × 40 × 40 μm cathode volume with 8,000,000 numerical cubes, the cathode involving three individual phases: 1) LiCoO2 as active material, 2) pores or electrolyte, and 3) additives (polyvinylidene fluoride + carbon black) is reconstructed. The microstructural statistical properties required in the reconstruction process are extracted from 2D focused ion beam/scanning electron microscopy images or obtained by analyzing the powder mixture used to make the cathode. Characterization of the reconstructed cathode gives important structural and transport properties including the two-point correlation functions, volume-specific surface area between phases, tortuosity and geometrical connectivity of individual phase.