Ag3.6Mo9Se11: Premier compose´a`clusters Mo9 dans des motifs Mo9Se11

Reversible Electrochemical Insertion/Extraction of Mg and Li Ions for Orthorhombic Mo9Se11with Cluster Structure

“…13 Downloaded on 2018-05-12 to IP anisotropic channel character, would not allow filling of a larger part of the vacant sites although the number of them is high in o-Mo 9 Se 11 . 21 On the other hand, in the case of Chevrel compounds, Mo 6 X 8 (X = S, Se), with three-dimensional diffusion channel, 33 it is reported that both Li-and Mg-systems show the similar order capacity comparable with the theoretical capacity 11,12,[17][18][19][20]34,35 deduced from the molecular orbital model, 23 in which extra four electrons per formula unit form closed-shell configuration of bonding orbitals. The threedimensional diffusion channel could work effectively to reduce the energy increase by Coulomb repulsion between the inserted ions.…”

“…In the XRD pattern of o-Mo 9 Se 11 , the change of relative peak intensity from o-Ag 3.6 Mo 9 Se 11 , which is due to the extraction of Ag and the shift of site position for Mo and Se in the unit cell, was also confirmed as observed in the previous report. 21 The lattice constants of synthesized o-Mo 9 Se 11 are a = 11.993(4) Å, b = 13.099(4) Å, c = 11.056(3) Å, respectively. 27 The difference from the previous reported lattice parameter 21 is below 0.3%, indicating most of Ag-ions are successfully extracted as reported in the previous study.…”

“…21 The lattice constants of synthesized o-Mo 9 Se 11 are a = 11.993(4) Å, b = 13.099(4) Å, c = 11.056(3) Å, respectively. 27 The difference from the previous reported lattice parameter 21 is below 0.3%, indicating most of Ag-ions are successfully extracted as reported in the previous study. 21 As far as analyzed by EDX, the presence of Ag was not detected.…”

“…From the view point of crystal structure, since ten insertion-sites exist per Mo 9 Se 11 unit, 21 the theoretical capacity is calculated to be 155 mAh/g for o-Li x Mo 9 Se 11 (x = 10). On the other hand, in the previous report of Mo 9 cluster chalcogenides, only a part of insertion sites, which is below 50% of the total sites, are occupied and the occupancy seems to be rather dominated by the oxidation state of host material; 22,24,[28][29][30] Mo 9 X 11 (X = S, Se) appears to be stabilized by accepting about four electrons for all compounds. However, estimation of theoretical capacity from the valence change of only one Mo-ion is difficult in o-Mo 9 Se 11 because the valence of Mo is averaged one by nine atoms within Mo 9 -cluster unit and becomes non-integer value, +22/9 per Mo.…”

“…The crystal structure of o-Mo 9 Se 11 is orthorhombic belonging to the space group Cmcm 21,22 and consists of Mo 9 Se 11 units ( Fig. 1(a)).…”