Modeling of Stresses and Strains during (De)Lithiation of Ni3Sn2-Coated Nickel Inverse-Opal Anodes.

Tin alloy-based anodes supported by inverse-opal nanoscaffolds undergo large volume changes from (de)lithiation during cyclic battery (dis)charging, affecting their mechanical stability. We perform continuum mechanics-based simulation to study the evolution of internal stresses and strains as a function of the geometry of the active layer(s): (i) thickness of Ni3Sn2 single layer (30 and 60 nm) and (ii) stacking sequence of Ni3Sn2 and amorphous Si in bilayers (60 nm thick). For single Ni3Sn2 active layers, a thinner layer displays higher strains and stresses, which are relevant to mechanical stability, but causes lower strains and stresses in the Ni scaffold. For Ni3Sn2-Si bilayers, the stacking sequence significantly affects the deformation of the active layers and thus its mechanical stability due to different lithiation behaviors and volume changes.