The ionic conductivities of lithium fluoride thin films prepared by radio-frequency sputtering have been compared when in contact with different oxide substrates (Al2O3, TiO2, SiO2). Thickness-dependent measurements of the normalized conductance allow us to separate bulk and interface contributions. The interfacial excess conductivities are discussed on the basis of interfacial space charge models considering depletion or accumulation of lithium vacancy point defects as a consequence of the presence of two-dimensional and one-dimensional defects. (C) 2012 Elsevier B.V. All rights reserved.