Strain Coupling During Lithiation of a Fe3O4/SrTiO3 Epitaxial Thin Film

Strain-related issues are of the extraordinary importance for the performance of lithium ion batteries. For the conversionand alloy-types electrode compounds, the cracks originated from the electrochemicallyinduced-strains are considered as the primary reason for their capacity fading and short cycle life[1]. Further, the transport of lithium ions themselves is affected by the strain during insertion/extraction into/from active materials. Besides electrochemically-induced-strain instigated inside single particles, the external strain also exist due to solid-to-solid interfaces in the electrode. For example, during operation, each particle undergoes volumetric changes, which generates external strain to neighboring particles. In all-solid-state-batteries, external strain is a more important issue due to the solid nature of electrolyte. Even though the electrode in lithium ion batteries can be influenced by various external and internal sources of strains, it is still not clear that how they affect the kinetics of lithiation. Especially, the coupling effect of electrochemically induced strain and external strain on electrode materials have not been investigated yet.