A comprehensive research coupling experiment and computation has been performed to understand the phase transition of Na3SbS4 and to synthesize cubic Na3SbS4 (c-Na3SbS4), a high temperature phase of Na3SbS4 that is difficult to be preserved when cooled down to ambient temperature. The formation of c-Na3SbS4 is verified by Rietveld refinement, nuclear magnetic resonance spectroscopy as well as electrochemical impedance spectroscopy. Unlike tetragonal Na3SbS4 (t-Na3SbS4) appearing phase transition at high temperature, c-Na3SbS4 is stable not just at room temperature but also sustaining thermal cycling up to at least 200 degrees C. Both experiment and theoretical calculation reveal that the ionic conductivity of c-Na3SbS4 is higher than that of t-Na3SbS4, though the values are in the same order of magnitude. Both structures allow fast ion transport. All-solid-state cells with c-Na3SbS4 solid electrolyte demonstrate superior Coulombic efficiency, high specific capacity, and relatively good cycling stability. Na3SbS4 solid electrolyte is promising for all-solid-state sodium-ion batteries. (c) 2017 Elsevier Ltd. All rights reserved.