Method to deduce the critical size for interfacial delamination of patterned electrode structures and application to lithiation of thin-film silicon islands

Recent experiments have suggested that there is a critical size for patterned silicon (Si) thin film electrodes for delamination from a current collector during lithiation and delithiation cycling. However, no existing theories can explain this phenomenon, in spite of its potential importance in designing reliable electrodes for high-capacity lithium-ion batteries. In this study, we show that the observed delamination size effect can be rationalized by modeling thin film delamination in the presence of large scale interfacial sliding. A method is proposed to deduce the critical size for delamination based on the critical conditions for the nucleation and growth of edge or center cracks at the film-substrate interface under plane strain or axisymmetric conditions. Applications to lithiation of thin-film Si islands give results in excellent agreement with experimental observations.

► We model delamination of patterned silicon thin film electrodes from a substrate. ► We perform plane strain and axisymmetric energy analysis of the interfacial cracks. ► We examine effect of the island size on the behavior of interfacial cracks. ► A critical island size to control/avoid film delamination is identified. ► The results are in good agreement with the experimental observations.