TY - JOUR
T1 - New intermetallic phases in the Cu-Li-Sn system: the lithium-rich phases Li3CuSn and Li6Cu2Sn3
AU - Fürtauer, Siegfried
AU - Effenberger, Herta Silvia
AU - Flandorfer, Hans
N1 - Publisher Copyright:
© 2016 by De Gruyter.
PY - 2016/2
Y1 - 2016/2
N2 - The Li-rich ternary intermetallic compounds with the idealized end-member compositions Li3CuSn (CSD-427099) and Li6Cu2Sn3 (CSD-427100) were synthesized from the pure elements by induction melting in Ta crucibles and annealing at 400°C. Both powder and single-crystal XRD investigations were performed. Li3CuSn crystallizes in space group P6/mmm [a=4.5769(2), c=8.461(2) Å; wR2=0.073 for 180 unique F2-values and 25 free variables]. All atoms are located along [00z], [1/3 2/3 z] and [2/3 1/3 z]; individual sites are arranged in layers parallel to (00.1). One site is fully, one partially occupied by Sn atoms. Fully but mixed occupation with Cu and Li atoms was found for one site. The remaining electron-density distribution resulting from the strong anisotropic displacement parallel to the c axis is considered in four further sites, which are mixed occupied with (Li, Cu, ?), but modelled solely by Li atoms. The crystal structure exhibits analogies with that of Li2CuSn (F4¯3m); comparable layers occur parallel to {111} but the stacking sequence and packing density differs adopting cubic symmetry. In Li6Cu2Sn3 [space group R3¯2/m, a=4.5900(2), c=30.910(6) Å; wR2=0.039 for 253 unique F2-values for 25 free variables] all atoms are arranged again at (00z), (1/3 2/3 z) and (2/3 1/3 z). Three sites are fully occupied (two by Sn atoms, a further one by Li atoms). Three additional positions are mixed occupied by Cu and Li atoms. The crystal structure is closely related to that of the binary phases Li13Sn5 and Li5Sn2; the substitution of Li by Cu atoms and vice versa is evident. The structural relationship to Li13Ag5Si6, which is permeable for Li ions, makes the title compound interesting as anode material in Li-ion batteries.
AB - The Li-rich ternary intermetallic compounds with the idealized end-member compositions Li3CuSn (CSD-427099) and Li6Cu2Sn3 (CSD-427100) were synthesized from the pure elements by induction melting in Ta crucibles and annealing at 400°C. Both powder and single-crystal XRD investigations were performed. Li3CuSn crystallizes in space group P6/mmm [a=4.5769(2), c=8.461(2) Å; wR2=0.073 for 180 unique F2-values and 25 free variables]. All atoms are located along [00z], [1/3 2/3 z] and [2/3 1/3 z]; individual sites are arranged in layers parallel to (00.1). One site is fully, one partially occupied by Sn atoms. Fully but mixed occupation with Cu and Li atoms was found for one site. The remaining electron-density distribution resulting from the strong anisotropic displacement parallel to the c axis is considered in four further sites, which are mixed occupied with (Li, Cu, ?), but modelled solely by Li atoms. The crystal structure exhibits analogies with that of Li2CuSn (F4¯3m); comparable layers occur parallel to {111} but the stacking sequence and packing density differs adopting cubic symmetry. In Li6Cu2Sn3 [space group R3¯2/m, a=4.5900(2), c=30.910(6) Å; wR2=0.039 for 253 unique F2-values for 25 free variables] all atoms are arranged again at (00z), (1/3 2/3 z) and (2/3 1/3 z). Three sites are fully occupied (two by Sn atoms, a further one by Li atoms). Three additional positions are mixed occupied by Cu and Li atoms. The crystal structure is closely related to that of the binary phases Li13Sn5 and Li5Sn2; the substitution of Li by Cu atoms and vice versa is evident. The structural relationship to Li13Ag5Si6, which is permeable for Li ions, makes the title compound interesting as anode material in Li-ion batteries.
KW - crystal structure
KW - intermetallic compounds
KW - Li-ion battery
KW - lithium; single-crystal XRD
KW - lithium
KW - CRYSTAL-STRUCTURE
KW - TIN
KW - X-RAY-DIFFRACTION
KW - ANODE
KW - single-crystal XRD
KW - ELECTROCHEMICAL LITHIATION
UR - http://www.scopus.com/inward/record.url?scp=84958162969&partnerID=8YFLogxK
U2 - 10.1515/zkri-2015-1884
DO - 10.1515/zkri-2015-1884
M3 - Article
SN - 2194-4946
VL - 231
SP - 79
EP - 87
JO - Zeitschrift für Kristallographie - Crystalline Materials
JF - Zeitschrift für Kristallographie - Crystalline Materials
IS - 2
ER -