Kinetically Stabilized Cation Arrangement in Li₃ YCl₆ Superionic Conductor during Solid-State Reaction.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Metastable materials are typically discovered through trial-and-error synthesis.
• Understanding the kinetic stabilization mechanisms of metastable materials is limited.
• Superionic conductors are crucial for energy storage applications.

Purpose of the Study:

• To discover and characterize a novel metastable phase of Li3YCl6.
• To elucidate the kinetic stabilization mechanisms of the discovered metastable phase.
• To investigate the ionic conductivity properties of the metastable phase.

Main Methods:

• In situ X-ray diffraction was used to synthesize and identify the metastable beta-Li3YCl6 phase.
• Neutron diffraction was employed to determine the crystal structure of beta-Li3YCl6.
• Computational methods were used to calculate ion migration barriers.

Main Results:

• A novel metastable superionic conductor, beta-Li3YCl6, was synthesized below 600 K.
• Beta-Li3YCl6 exhibits a hexagonal close-packed Cl- arrangement, similar to the stable alpha-Li3YCl6 phase.
• Higher Li+ ion conductivity and lower activation energy were observed in beta-Li3YCl6 compared to alpha-Li3YCl6.
• Computational studies revealed low Li+ and high Y3+ migration barriers, explaining the kinetic stabilization of beta-Li3YCl6.

Conclusions:

• The combination of in situ diffraction and computational migration energy calculations facilitates the understanding and discovery of kinetically stabilized metastable materials.
• The high Y3+ migration barrier in beta-Li3YCl6 is responsible for its kinetic stabilization.
• This approach enables rapid discovery of new metastable materials with potential applications in energy storage.