The Influences of Excess Sodium on Low‐Temperature Na SICON Synthesis

Controlling the materials chemistry of the solid‐state ion conductor Na SICON is key to realizing its potential utility in emerging sodium‐based battery technologies. We describe here the influence of excess sodium on phase evolution of sol‐gel synthesized Na SICON . Alkoxide‐based sol‐gel processing was used to produce powders of Na 3 Zr 2 PSi 2 O 12 Na SICON with 0‐2 atomic % excess sodium. Phase formation and component volatility were studied as a function of temperature. Na SICON synthesis at temperatures between 900‐1100°C with up to 2% excess sodium significantly reduced the presence of zirconia, sodium phosphate, and sodium silicate secondary phases in fired Na SICON powders. Insights into the role of sodium on the phase chemistry of sol‐gel processed Na SICON may inform key improvements in Na SICON development.