Lithiation Induced Stress Concentration for 3D Metal Scaffold Structured Silicon Anodes

Silicon is a promising material for next generation lithium ion battery anodes, because of its high theoretical specific capacity and relatively low operating voltage. However, due to the significant volume change during its lithiation/de-lithiation, the cycle life of Si-based anodes is restricted. A novel Si-coated inverse opal-structured anode, designed to mitigate the negative impacts of cycling-induced volume changes, is investigated in this study. The lithiation-induced stresses in the anode are predicted via coupled electrochemical- and mechanics-based finite element (FE) models. In this study, the effects of various cycling conditions and anode design parameters on the lithiation-induced stresses are explored, including the charging C-rate, thickness of the Si coating layer, and structural and mechanical properties of the supporting scaffold. It is found that the inverse opal anode structure could improve the uniform distribution of lithium in Si host material. It is also found that the anode structural design parameters have large influences on the stress concentrations in the Si coating layer, as well as in the supporting scaffold of the anode.