Revision of the Li13Si4 structure

Area of Science:

• Solid-state chemistry
• Materials science
• Crystallography

Background:

• The lithium-silicon system contains various lithium-rich phases, including Li13Si4.
• Previous structural determination of Li13Si4 by Frank et al. (1975) showed discrepancies with experimental X-ray diffraction data.
• Accurate structural information is crucial for understanding the properties and potential applications of intermetallic compounds.

Purpose of the Study:

• To redetermine the crystal structure of Li13Si4 with high accuracy.
• To resolve discrepancies observed in previous crystallographic studies of Li13Si4.
• To provide a reliable structural model for the Li13Si4 phase.

Main Methods:

• Single-crystal X-ray diffraction was employed for structural analysis.
• Experimental X-ray diffraction patterns were carefully analyzed.
• Anisotropic refinement of atomic displacement parameters and introduction of a split Li site were performed.

Main Results:

• The refined structure of Li13Si4 exhibits significant differences compared to the previously reported structure.
• A split position for one lithium site was identified with an occupancy ratio of 0.838(7):0.162(7).
• The structure features isolated Si atoms and Si-Si dumbbells, with Si atoms exhibiting 12- or 13-coordination.

Conclusions:

• The redetermined structure of Li13Si4 offers a more accurate representation based on high-quality single-crystal data.
• The findings highlight the importance of precise crystallographic analysis for complex intermetallic phases.
• This work provides a foundational structural understanding for further investigations into the Li-Si system.