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

ABSTRACT

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.