Atomic-Scale Mechanisms of Sliding along an Interdiffused Li–Si–Cu Interface

Abstract

We perform ab initio calculations on the shear deformation response of the interdiffused Li–Si–Cu phase structure existing between a lithiated Si electrode and a Cu current collector. We show that the formation of well-delineated and weakly bonded Si–Cu and Li–Cu crystalline atomic layers within this phase structure facilitates interface sliding. However, sliding can be terminated by the formation of LiSi₃ compounds across these atomic layers, which causes the abrupt capacity fade of the electrode after repeated cycling