Amorphous Li2S-GeS2 solid electrolyte thin films were prepared using pulsed laser deposition (PLD) at the compositions of 67-83 mol% Li2S. The ionic conductivities at room temperature increased with increasing Li2S contents and attained a maximum value of 1.8 x 10(-4) S cm(-1) at the composition of 78 mol% Li2S. The obtained solid electrolyte thin film was applied to form an ideal electrode-electrolyte interface in all-solid-state batteries. The all-solid-state lithium cell using LiCoO2 coated with the solid electrolyte thin film operated as a lithium secondary battery at room temperature. (c) 2013 Elsevier B.V. All rights reserved.