Anisotropic Electrochemical Lithiation of Single Crystal Silicon Electrodes Assembled in an All-Solid-State Battery Configuration

High Resolution Image Download MS PowerPoint Slide Electrochemical lithiation of single-crystal silicon ( c -Si) electrodes with different surface orientations of (110), (100), and (111) was studied in an all-solid-state lithium-ion battery configuration. A lithium phosphorus oxynitride (LiPON) solid-electrolyte layer was sputter-deposited on the c -Si wafer, and a piece of Li metal foil was further incorporated to yield a solid-state half-cell with a configuration of c -Si/LiPON/Li. After electrochemical lithiation, their cross sections were analyzed using various techniques. Amorphous lithium silicide ( a -Li x Si) layers were generated at the c -Si/LiPON interface due to the insertion of lithium-ion from LiPON to c -Si lattices, followed by amorphization. Whereas a -Li ∼1 Si was the predominant Li x Si species in the lithiated Si(110) and (100), two distinct Li x Si species, barely lithiated a -Li ∼0 Si and almost fully lithiated a -Li ∼3.4 Si, formed in the lithiated Si(111) electrodes.