Due to the small size of the Si particles, and in order to avoid the generation of an excessively dense mesh, which would result in prohibitive simulation times, the Si particles were merged together in a homogenized domain. Additionally, in order to guarantee the connectivity of the CBD network, which is not obvious from the particle-like assumption of the CGMD simulations, the CBD phase was further treated with a 'connect-erode' process, as illustrated in Figure . In short, CBD particles are first connected with a cylinder of the same diameter as the particles themselves and the interface between the CBD and the electrolyte phases is eroded in order to recover the original volume. Lastly, a tetrahedral finite element mesh was generated from the voxelated microstructers, with the open-source Iso2mesh software .