TY - JOUR
T1 - A comparison of the transport properties of lithium-stuffed garnets and the conventional phases Li3Ln3Te2O12
AU - Cussen, Edmund
AU - Yip, Thomas Wai Sing
AU - O'Neil, Gemma
AU - O'Callaghan, Michael P.
PY - 2011/2
Y1 - 2011/2
N2 - The structures of new phases Li6CaLa2Sb2O12 and Li6.4Ca1.4La2Sb2O12 have been characterised using neutron powder diffraction. Rietveld analyses show that both compounds crystallise in the space group la3̄d and contain the lithium cations in a complex arrangement with occupational disorder across oxide tetrahedra and distorted oxide octahedra, with considerable positional disorder in the latter. Variable temperature neutron diffraction experiments on Li6.4Ca1.4La2Sb2O12 show the structure is largely invariant with only a small variation in the lithium distribution as a function of temperature. Impedance spectroscopy measurements show that the total conductivity of Li6CaLa2Sb2O12 is several orders of magnitude smaller than related lithium-stuffed garnets with σ=10−7 S cm−1 at 95 °C and an activation energy of 0.82(3) eV. The transport properties of the conventional garnets Li3Gd3Te2O12, Li3Tb3Te2O12, Li3Er3Te2O12 and Li3Lu3Te2O12 have been evaluated and consistently show much lower values of conductivity, σ≤4.4×10−6 S cm−1 at 285 °C and activation energies in the range 0.77(4)≤Ea/eV≤1.21(3).
AB - The structures of new phases Li6CaLa2Sb2O12 and Li6.4Ca1.4La2Sb2O12 have been characterised using neutron powder diffraction. Rietveld analyses show that both compounds crystallise in the space group la3̄d and contain the lithium cations in a complex arrangement with occupational disorder across oxide tetrahedra and distorted oxide octahedra, with considerable positional disorder in the latter. Variable temperature neutron diffraction experiments on Li6.4Ca1.4La2Sb2O12 show the structure is largely invariant with only a small variation in the lithium distribution as a function of temperature. Impedance spectroscopy measurements show that the total conductivity of Li6CaLa2Sb2O12 is several orders of magnitude smaller than related lithium-stuffed garnets with σ=10−7 S cm−1 at 95 °C and an activation energy of 0.82(3) eV. The transport properties of the conventional garnets Li3Gd3Te2O12, Li3Tb3Te2O12, Li3Er3Te2O12 and Li3Lu3Te2O12 have been evaluated and consistently show much lower values of conductivity, σ≤4.4×10−6 S cm−1 at 285 °C and activation energies in the range 0.77(4)≤Ea/eV≤1.21(3).
KW - ionic conduction
KW - diffraction
KW - crystallography
KW - garnet
KW - lithium
UR - http://www.scopus.com/inward/record.url?scp=79551681939&partnerID=8YFLogxK
U2 - 10.1016/j.jssc.2010.12.021
DO - 10.1016/j.jssc.2010.12.021
M3 - Article
VL - 184
SP - 470
EP - 475
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
SN - 0022-4596
IS - 2
ER -