Li–O2 batteries have attracted a lot of attention because of their high theoretical capacity. Due to the high complexity of these systems, deep understanding of the discharge mechanism is still needed to push the state-of-the-art performance of Li–O2 batteries to the theoretical one. A universal multiscale model combining nucleation theory, detailed reaction kinetics, and mass transport is presented in this article, which encompasses the impacts of discharge rate, electrolyte property and electrode surface properties on the discharge capacity of Li–O2 batteries and on the morphology of the Li2O2 arising from its nucleation process.

We report a comprehensive multiscale model describing charge processes of Li-O batteries. On the basis of a continuum approach, the present model combines mathematical descriptions of mass transport of soluble species (O, Li, LiO) and elementary reaction kinetics, which are assumed to be dependent on the morphology of the LiO formed during discharge. The simulated charge curves are in agreement with previously reported experimental studies. The model along with the assumed reaction mechanisms provides physical explanations for the two-step charge profiles. Furthermore, it suggests that these charge profiles depend on the size of the LiO particles, which are determined by the applied current density during discharge. Therefore, the model underlines the strong link between discharge and charge processes.