Electronic structure and chemical bonding of LiYSi

The electronic structure of the ternary silicide LiYSi (ZrNiAl type, P  6¯2m N°189, a = 702.3, c = 421.2 pm) is examined from ab initio with an assessment of the properties of chemical bonding. The compound is found semi-conducting with a very small gap and the chemical bonding is found mainly between Y and Si as well as Li–Si with differentiated Li–Si1/Li–Si2. The structure with totally de-intercalated Li keeps the characteristics of LiYSi with a reduction of the c/a ratio and of the volume albeit with less stability than binary YSi with orthorhombic CrB type structure. The electronic structure calculations indicate the possibility of an at least partial delithiation Li1−xYSi while keeping the hexagonal structure.

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► LiYSi is found semi-conducting with a very small gap from ab initio investigations.
► Chemical bonding is mainly between Y and Si and Li–Si bond is differentiated.
► The Li de-intercalated structure keeps the characteristics of LiYSi with smaller c/a and volume.
► The calculations indicate at least partial delithiation Li1−xYSi while keeping the hexagonal structure.