Sodium-Ion Solid-State Electrolyte Powder NZSPO 1–5 μm (Na3Zr2Si2PO12)

The powder was dehydrated using isopropyl alcohol, followed by ball milling to achieve uniform dispersion, and then vacuum-dried.
Approximately 0.3 g of the powder was uniaxially dry-pressed at 150 MPa and held for 1 minute.
The green pellets were sintered at approximately 1150 °C. During sintering, a powder-bed covering was optionally used to suppress sodium volatilization.

After sintering, the pellets were ground and polished according to surface smoothness and mechanical hardness. Coarse grinding was first performed, followed by fine grinding using sandpapers with grit sizes ranging from 100 to 2500 mesh. The surface was then polished to near-mirror finish.

Gold was sputtered onto both sides of the pellets, and the coating quality was evaluated. A two-point resistance below 100 Ω measured over a 10 mm distance was considered acceptable. Electrochemical impedance spectroscopy (EIS) measurements were then conducted. The electrochemical workstation was set to the highest possible response frequency, with a test frequency range of 10 MHz to 1 Hz.

Notes:
The dry-pressing parameters may be optimized according to the actual condition of the powder, and the applied pressure can be adjusted accordingly.
The test results are influenced by multiple factors, including sintering conditions, surface polishing quality, gold coating effectiveness, and testing temperature. This procedure is provided for reference only, and users are encouraged to further optimize the protocol based on their specific requirements.