Solid State Ionics, Vol.302, 102-106, 2017
Stability of NASICON materials against water and CO2 uptake
The stability in ambient conditions of a scandium-based NASICON material, Na(3.4)Sc(2)Si(0.4)AP(2.6)O(12), was investigated using impedance spectroscopy, thermogravimetry/differential scanning calorimetry (TG/DSC) and multinUclear magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR). The presence of H2O and CO2 in samples stored in ambient air could be evidenced as well as its impact on the ionic conductivity of the samples. The detected amounts of water and CO2 in the samples had no influence on the measured conductivities at room temperature, which confirmed the absence of protonic conduction in hydrated samples. A loss of conductivity during heating of hydrated samples was due to a loss of contact between the ceramic and the electrode used for the conductivity measurement. The recommendation for handling of NASICON-type materials is therefore: samples require storage in an Arfilled glove box or in a dry environment to avoid artefacts during high temperature measurements. Nevertheless, the stability of the NASICON-type materials is confirmed since their conductivity is not affected by the moisture. (C) 2016 Elsevier B.V. All rights reserved.