Abstract

Potential energy surface screening combined with density functional computations reveal that the Li32Si18 lowest energy structure consists of Si4 Y-shaped and Si5-pentagonal moieties, as observed in the crystalline Zintl-phase Li12Si7. The Li32Si18 system can be interpreted as an assembly of Li10Si4 (Si4-Y) and Li6Si5 (Si5-pentagonal) clusters, showing a clear growth pattern towards a material assembled from clusters. Chemical bonding analysis shows that the silicon atoms are strongly connected by covalent bonds, with a significant electron transfer from the lithium resulting in primarily electrostatic Li-Si interactions. This study establishes a structural relationship between Li-Si compounds at sub-nano, nano, and macro scales, which, together with the abundant literature on Zintl-phases of lithium silicides, may open new routes for materials design.