In this work, for the first time, we systematically evaluated the temperature-dependent long-term stability of Na-doped SrSiO3 super ionic conductors. The total conductivity of the Sr0.6Na0.4SiO2.8(40SNS) was monitored in situ by electrochemical impedance spectroscopy. The conductivity of the 40SNS at 700 degrees C degraded within 1 h due to the crystallization of Na2Si2O5. However, at 450 degrees C, the initial conductivity of the 40SNS was firmly maintained for 260h without any observable phase transition. These results demonstrate the existence of a threshold temperature regime that suppresses the crystallization kinetics of the amorphous phase of Na-doped SrSiO3 materials. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.