Finite Element Modeling of the Cycle Characteristics of Li–O2 Secondary Batteries Considering Surface- and Solution-Route Discharge Reactions

Abstract

Model-based development is an effective approach in terms of obtaining design guidelines for lithium–oxygen secondary batteries (LOBs). In this study, a model simulating the charge/discharge cycle was developed using the finite element method, which enabled us to investigate the factors governing the cyclability of LOBs by conducting virtual cycle tests. In this modeling, we particularly considered that the discharge can proceed via two different routes: surface and solution routes. As an example demonstrating the usefulness of the virtual tests based on the developed model, we evaluated the effects of changes in parameters related to oxygen transport properties on the deposition and dissolution sites of lithium peroxide (Li2O2) generated in the porous cathode of an LOB via the surface and solution routes, respectively, and hence investigated the effects on the cyclability. The proposed model enables various validations that are extremely difficult to carry out using an experimental approach.