A diffusion–reaction–deformation coupling model for lithiation of silicon electrodes considering plastic flow at large deformation

Silicon (Si) is extensively used as an electrode in lithium (Li) ion batteries for its superiority in the charging capacity. However, the lithiation of Si would induce large deformation and significant stress jump across a two-phase interface in Si electrodes and might eventually lead to structure failure of batteries. To improve the performance and life of Li ion batteries, it is of great importance to exactly model the lithiation process. In the past decade, although many models have been developed for the lithiation, most of them just relate the deformation with the diffusion, without considering the effect of electrochemical reactions, so that they cannot simulate the formation of the two-phase interface. In this paper, we aim to develop a fully coupling diffusion–reaction–deformation model for large deformation cases and apply it to simulate the lithiation process, where a reaction barrier effect is proposed to describe the formation of the two-phase interface due to fast reaction and the mechanical behaviors of Si electrodes such as large plastic flow during lithiation process are predicted.