Synthesis and Characterization of Sodium-based Solid Electrolytes

Starting materials Na₂CO₃ (99.5%, Alfa Aesar), Gd₂O₃ (99.9%,
Thermo Scientific Chemicals), and SiO₂ (99.5%,
Thermo Scientific Chemicals) were dried before use. For doped NGS
compounds, ZrO₂ (99.7%, Thermo Scientific Chemicals) and
MgO (99.95%, Thermo Scientific Chemicals), also dried before use,
were added to the starting mixture. Fritsch Pulverisette 6 was used
for ball milling experiments (ZrO₂ vials (80 mL), and balls
were used for milling). The ball-to-powder weight ratio was 10:1.
BASE discs of 12 mm diameter and 1 mm thick were obtained from Ionotec
Ltd., England. Polycrystalline P2-Na_0.7Mn_0.9Mg_0.1O₂ (NMO) was synthesized according to
the previous report.^{33 (link)} The crystal structure
and phase purity of synthesized materials were determined via XRD
using a Bruker D8 Discover diffractometer and Cu Kα radiation
(40 kV; 40 mA). Scans were recorded between 10 and 60°. Rietveld
Refinement was performed by using FullProf software.