Enabling Facile Synthesis and High Sodium Ionic Conductivity in NZTO Solid Electrolyte by Substituting Fe³

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Solid electrolytes (SEs) are crucial for safe, high-energy-density storage devices.
• Layered oxide SEs offer stability and reasonable conductivity, but improvements are needed.
• Na₂Zn₂TeO₆ (NZTO) exhibits high ionic conductivity among layered oxides.

Purpose of the Study:

• To enhance the ionic conductivity and reduce the synthesis temperature of Na₂Zn₂TeO₆ (NZTO) solid electrolytes.
• To investigate the effect of iron (Fe³⁺) substitution on the structural and electrochemical properties of NZTO.
• To evaluate the performance of Fe³⁺-substituted NZTO in all-solid-state batteries.

Main Methods:

• Partial substitution of Zn²⁺ with Fe³⁺ in the Na₂Zn₂TeO₆ layered oxide structure.
• Synthesis of pristine and Fe³⁺-substituted NZTO at reduced temperatures.
• Characterization of ionic conductivity and structural phase purity.
• Fabrication and testing of solid-state battery cells using the synthesized electrolytes.

Main Results:

• Achieved a pure P2-NZTO phase at 750°C, a reduction from 900°C for pristine NZTO.
• Increased ionic conductivity from 0.469 mS/cm to 0.850 mS/cm at 25°C with 0.1 Fe substitution.
• Demonstrated a 12.9% capacity enhancement and improved stability in solid-state cells with Fe³⁺-substituted NZTO.

Conclusions:

• Fe³⁺ substitution is an effective strategy to enhance the performance of layered oxide solid electrolytes.
• Reduced sintering temperatures and improved ionic conductivity make Fe³⁺-substituted NZTO a promising candidate for all-solid-state batteries.
• The study confirms the potential of this modified material for advanced energy storage applications.