Novel Solid-State Electrolyte Na₃La₅Cl₁₈ with High Stability and Fast Ionic Conduction.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Recent synthesis of LaCl3-based lithium superionic conductors inspired further research.
• Exploration of LaCl3-based materials for sodium superionic conductors is an emerging area.

Purpose of the Study:

• To investigate the potential of a LaCl3-based system as a sodium superionic conductor.
• To evaluate the properties and stability of a novel sodium superionic conductor.

Main Methods:

• Density functional theory (DFT) calculations.
• Molecular dynamics (MD) simulations.
• Grand potential phase diagram analysis.

Main Results:

• Identified Na3La5Cl18 as a stable compound with low energy-above-hull (18 meV/atom).
• Achieved high Na+ conductivity (1.3 mS/cm at 300 K) and a wide electrochemical window (0.41-3.76 V).
• Demonstrated high chemical interface stability with various high-potential sodium cathode materials.

Conclusions:

• LaCl3-based frameworks are suitable building blocks for both lithium-ion and sodium-ion batteries.
• Na3La5Cl18 is a promising candidate for solid-state sodium-ion battery electrolytes.
• This study expands the design principles for solid superionic conductors.