A new lithium chalcogenidotetrelate, denoted as LiChT phase, with the elemental combination Li/Sn/S was synthesized as solvent-free and solvent-containing salts. We present and discuss syntheses, crystal structures, spectroscopic and thermal properties of the phases, as well as the Li + ion conductivity of Li 4 SnS 4 , which is formally related to the thio-LISICON parent system Li 4 GeS 4 , and thus represents the first member of a new thiostannate-LISICON family. The solvent-free title compound shows a very promising Li + ion conductivity of 7 × 10 −5 S·cm −1 at 20°C and 3 × 10S·cm −1 at 100°C, which is exceptionally high for a ternary compound. Activation energies for the lithium ion transport measured via impedance spectroscopy (0.41 eV) correlate reasonably well with the values (0.29 to 0.33 eV) deduced from ionic mobility studies by 7 Li solid-state NMR spectroscopy. NMR two-time correlation functions suggest the occurrence of an additional, geometrically more restricted, ultraslow-motional process down to 121 K.

Five new lithium chalcogenidotetrelates, so-called "LiChT" phases, with the elemental combination Li/Sn/Se, Li 4 [SnSe 4 ] (1), 1 ∞ {Li 2 [SnSe 3 ]} (2), and the respective solvates Li 4 [SnSe 4 ]•13H 2 O (3), Li 4 [Sn 2 Se 6 ]•14H 2 O (4), and Li 4 [SnSe 4 ]•16MeOH ( 5) were generated in single-crystalline form. We present and discuss syntheses, crystal structures, spectroscopic and thermal behavior, as well as Li + ion conducting properties of the phases that represent uncommon Li + ion conducting materials with a maximum conductivity found for 1 (σ 20°C = 2 × 10 −5 S•cm −1 , σ 100°C = 9 × 10 −4 S•cm −1 ). The latter was elucidated via impedance spectroscopy and further studied by electronic structure calculations, revealing vacancy migration as the dominant Li + transport mechanism. Thus, studies on a selenido-LISICON family were found to be a very interesting starting point for an extension of the LISICON-related solid state lithium ion conductors (SSLIC).

Li 8 (H 2 O) 29 ][Sn 10 O 4 S 20 ]·2H 2 O (1), which was obtained by an unusual synthesis pathway, represents the Li + salt of the supertetrahedral cluster anion [Sn 10 O 4 S 20 ] 8-. Due to the distinct hydration tendency of Li + , the crystal structure differs notably from that of a corresponding Cs + salt. Compound 1 extends the still very fragmentary

An improvement of lithium-ion batteries with regard to their reversible capacity, cycling stability, rate performance, and safety under repetitive charge and discharge still requires considerable research activity. However, graphite has remained the unexcelled material for the anode so far. Here, it is shown that two novel quaternary lithium-chalcogenidometalate phases, Li 4 MnGe 2 S 7 ( 1 ) and Li 4 MnSn 2 Se 7 ( 2 ), represent very promising new anode materials for lithium-ion cells in that they achieve specifi c lithium storage capacities higher than that of the commercially used graphite, and display an excellent stability during cycling. These properties are based on the structural peculiarities of the phases, which adopt Wurtzite-related topologies and provide high structural fl exibility of the metal sulfi de or selenide bonds as advantageous pre-requisitions for a large ion accessible volume.

S. Dehnen and co‐workers present two novel quaternary lithium‐chalcogenidometalate phases, Li4MnGe2S7 (1) and Li4MnSn2Se7 (2), that achieve specific lithium storage capacities higher than those of the commercially used graphite. , the phases display an excellent stability during cycling, thus representing very promising new anode materials for lithium‐ion cells.

Lithium Chalcogenidotetrelates: LiChT-Synthesis and Characterization of New Li + Ion Conducting Li/Sn/Se Compounds. -The new compounds (IV)-(VIII) are characterized by single crystal XRD and impedance spectroscopy. (IV) crystallizes in the orthorhombic space group Pnma with Z = 4. The structure contains isolated [SnSe4] 4tetrahedra with the Se atoms coordinated by four or five lithium ions. Hydrate (V) crystallizes in the orthorhombic space group P2 1 2 1 2 1 with Z = 4 and the MeOH adduct (VI) crystallizes in the tetragonal space group I4 with Z = 2. In these cases the [SnSe4] tetrahedra occupy the corners and the center of the unit cell with each Se atom being connected to four oxygen atoms via hydrogen bonds. (VII) crystallizes in the monoclinic space group Cc with Z = 4. Its anionic {[SnSe3] 2-}n substructure forms chains of corner-sharing [SnSe 4 ] tetrahedra. The [SnSe 4 ] tetrahedra of (VII) transform into dimeric [Sn2Se6] 4anions during the solvation/evaporation step. (VIII) crystallizes in the triclinic space group P1 with Z = 1. The compounds are potentially new solid state lithium ion conductors. -(KAIB, T.; BRON, P.; HADDADPOUR, S.; MAYRHOFER, L.; PASTEWKA, L.; JAERVI, T. T.; MOSELER, M.; ROLING, B.; DEHNEN*, S.; Chem. Mater. 25 (2013) 15, 2961-2969, http://dx.

The new compound Li4SnS4 (I) is synthesized from stoichiometric mixtures of Li2S, Sn, and sulfur (silica ampule, 600 °C, 24 h, 70% yield).

The crystalline selenido germanates [Li4(H2O)16]­[Ge4Se10]·4.3H2O (1), [{Li4(thf)12}­Ge4Se10] (2), and [Li2(H2O)8]­[MnGe4Se10] (3) (thf = THF = tetrahydrofuran) were obtained by an extraction of a glassy ternary phase of the nominal composition Li4Ge4Se10 (=Li2S·2GeSe2) with water (1) or THF (2) and slow evaporation of the solvent or by being layered with MnBr2 in H2O/MeOH (3), respectively. The compounds contain known selenido germanate anions, however, for the first time with Li+ counterions. This is especially remarkable for the prominent ∞ 3{[MnGe4Se10]2–} open-framework structure, which was reported to crystallize with (NMe4)+, Cs+, Rb+, and K+ counterions, but it has not yet been realized with the smallest alkali metal cation. Impedance spectroscopic studies on Li4Ge4Se10 classify the glassy solid as a moderate Li+ ion conductor.