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Understanding Li-ion batteries failure from first-principles calculations: The effect of lithiation on the Si/Cu interface in Si anodes

Maria Stournara (Brown univ), priya Johari (Brown University), Yue Qi (General Motors R&D), vivek shenoy (upenn)

Computational Materials Design via Multi-scale Modeling

Wed 9:00 - 10:30

Barus-Holley 190

We study the effect of lithiation on the Si/Cu interface in Si anodes from first principles calculations. Through ab initio molecular dynamics (AIMD) and density functional theory (DFT), we calculate the ideal work of separation between the two slabs, the segregation of Li at the interfacial zone and predict the critical shear stress for sliding of the interface. We demonstrate that (a) increasing presence of Li at the interface is responsible for delamination of Si from the Cu substrate, (b) Li segregates at the interface by 22% for highly lithiated structures (Li15Si4/Cu) and that (c) lithium’s presence at the interfacial zone results in sliding of the LixSi slab on Cu in agreement with experimental studies. To our knowledge, there has been no prior computational work that addresses the significant role of the interface from ab initio calculations. We believe that the results will provide a quantitative framework for the analysis of experimental measurements of deformation during lithiation/delithiation.