On the origin of anisotropic lithiation in crystalline silicon over germanium: A first principles study

- We examine the underlying reasons for the anisotropic lithiation of Si over Ge in the crystalline phase.
- Crystalline Si is lithiated in a layer-by-layer fashion, yielding a sharp amorphous-crystalline interface.
- Lithiated c-Ge exhibits a graded lithiation front, which proceeds much faster than that in c-Si.
- Lithiation behavior tends to be subject to the stiffness and dynamics of the host matrix.
- We reveal the origin and extended impacts of the anisotropic Si vs. isotropic Ge lithiation.