Synthesis, structure determination and magnetic susceptibilities of the oxides Ln3Li5Sb2O12 (Ln ≠ Pr, Nd, Sm)

A neutron diffraction study of the d0 and d10 lithium garnets Li3Nd3W2O12 and Li5La3Sb2O12

“…The garnets Li 3 Ln 3 Te 2 O 12 follow this stoichiometry and contain lithium on the tetrahedral site of the structure but show minimal ionic mobility with s 600 1C E10 À5 S cm À1 [6]. However, a number of lithium-containing garnets have long been known to form with unusual stoichiometries Li 5 Ln 3 M 2 O 12 where M is a pentavalent cation such as Ta 5+ , [7,8] Nb 5+ or Sb 5+ [9,10]. The Li + conductivity of Li 5 La 3 Ta 2 O 12 and Li 5 La 3 Nb 2 O 12 is around three orders of magnitude greater [3] than Li 3 Nd 3 Te 2 O 12 and at room temperature, s RT E10 À5 , is comparable to other crystalline Li + electrolytes [11].…”

“…Whilst structurally distorted garnets with reduced symmetry are known [14], the vast majority of garnets crystallise in the space group Ia3d. The limited number of structural reports of lithium-containing garnets often describe these phases in lower symmetry cubic groups such as I2 1 3 [7,9,10,15] or Ia3 [15] based on X-ray diffraction experiments which have poor sensitivity to lithium cations in these compounds. Here we present a neutron diffraction determination of the structure of two garnets Li 3 Nd 3 W 2 O 12 and Li 5 La 3 Sb 2 O 12 .…”

Synthesis and conductivities of the garnet-related Li ion conductors, Li5Ln3Sb2O12 (Ln=La, Pr, Nd, Sm, Eu)

“…In this respect, the synthesis of Li 5 Ln 3 Sb 2 O 12 (Ln=La, Pr, Nd, Sm) have been reported by Isasi et al [14,15]. However, there was no characterisation of the Li ion conductivity of these Sb containing garnets.…”

Lithium Ion Conduction in Oxides

“…[167] The first structural characterisations of lithium garnets relied on X-ray diffraction techniques and this led to a debate concerning both the stoichiometry and the lithium coordination environment of a number of cation-rich garnet phases with unusual stoichiometries such as Li 5 La 3 M 2 O 12 (M ¼ Nb, Ta, Sb). [168][169][170] As the prototype garnet structure fills all of the cation sites using a total of eight cations per formula unit it follows that in these lithium-rich garnets some additional sites must be occupied in order to accommodate ten cations per formula unit. Identification of these sites remained a considerable 6 and SiO 4 units shown as octahedra and tetrahedra respectively.…”