TY - JOUR

T1 - Single-crystal neutron diffraction on γ-LiAlO2

T2 - Structure determination and estimation of lithium diffusion pathway

AU - Wiedemann, Dennis

AU - Indris, Sylvio

AU - Meven, Martin

AU - Pedersen, Björn

AU - Boysen, Hans

AU - Uecker, Reinhard

AU - Heitjans, Paul

AU - Lerch, Martin

N1 - Financial support by the Deutsche Forschungsgemeinschaft (FOR 1277: “Mobilität von Lithiumionen in Festkörpern [molife]”) is gratefully acknowledged. This work is based on experiments performed at the RESI instrument operated by FRM II and the HEiDi instrument operated by RWTH Aachen and Forschungszentrum Jülich within the JARA-FIT initiative at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Garching, Germany.

PY - 2016/3/1

Y1 - 2016/3/1

N2 - γ-Lithium aluminum oxide is a paradigmatic example of an ultraslow lithium ion conductor. This characteristic plays a crucial role in its proposed and actual applications. Herein, we report on the outcome of single-crystal neutron diffraction studies at ambient and high temperature. Careful evaluation confirms the commonly assumed room-temperature structure as derived by powder neutron diffraction in 1965. At 1043 K, a split of the lithium position hints at the onset of intrinsic diffusion. Analysis of the negative scattering-length density using the maximum-entropy method (MEM) indicates a preference for a strongly curved diffusion pathway traversing octahedral voids between adjacent lithium sites. These results help to understand ultraslow lithium diffusion in well-ordered ionic solids on the microscopic scale and, ultimately, to establish structure-property relationships.

AB - γ-Lithium aluminum oxide is a paradigmatic example of an ultraslow lithium ion conductor. This characteristic plays a crucial role in its proposed and actual applications. Herein, we report on the outcome of single-crystal neutron diffraction studies at ambient and high temperature. Careful evaluation confirms the commonly assumed room-temperature structure as derived by powder neutron diffraction in 1965. At 1043 K, a split of the lithium position hints at the onset of intrinsic diffusion. Analysis of the negative scattering-length density using the maximum-entropy method (MEM) indicates a preference for a strongly curved diffusion pathway traversing octahedral voids between adjacent lithium sites. These results help to understand ultraslow lithium diffusion in well-ordered ionic solids on the microscopic scale and, ultimately, to establish structure-property relationships.

KW - anisotropic displacement parameters

KW - diffusion pathways

KW - high-temperature neutron diffraction

KW - lithium aluminum oxide

KW - maximum-entropy method

UR - http://www.scopus.com/inward/record.url?scp=84960965173&partnerID=8YFLogxK

U2 - 10.1515/zkri-2015-1896

DO - 10.1515/zkri-2015-1896

M3 - Article

AN - SCOPUS:84960965173

VL - 231

SP - 189

EP - 193

JO - Zeitschrift fur Kristallographie - Crystalline Materials

JF - Zeitschrift fur Kristallographie - Crystalline Materials

SN - 2194-4946

IS - 3

ER -