NASICON Membrane with High Ionic Conductivity Synthesized by High-Temperature Solid-State Reaction

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Sodium ion conductors are crucial for energy storage applications.
• Optimizing NASICON structure is key to improving ionic conductivity.
• Excess sodium doping is explored to enhance NASICON performance.

Purpose of the Study:

• To investigate the effect of excess sodium on NASICON structure and ion transport.
• To synthesize and characterize NASICON ceramic membranes with varying sodium content.
• To evaluate the ionic conductivity of modified NASICON materials.

Main Methods:

• Solid-state reaction (SSR) synthesis of NASICON (Na3Zr2Si2PO12) with 0%, 5%, and 10% excess Na.
• Characterization using Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and BET surface area analysis.
• Ionic conductivity measurements via impedance spectroscopy at room temperature.

Main Results:

• NASICON membranes with 10% excess Na exhibited improved structural properties.
• Optimal sintering at 1175 °C for 10 hours was determined for enhanced conductivity.
• The optimized 10% Na-excess NASICON membrane achieved an ionic conductivity of 4.72 × 10^-4 S/cm.

Conclusions:

• Excess sodium doping, particularly 10%, significantly improves NASICON ionic conductivity.
• Optimized synthesis conditions are critical for maximizing the performance of NASICON ion conductors.
• This study provides a pathway for developing superior NASICON-based materials for electrochemical devices.