Orthorhombic Crystal System for a Garnet-type Lithium-Ion Conductor

Area of Science:

• Solid-state chemistry and materials science.
• Crystallography and structural analysis.
• Ionic conductivity research.

Background:

• Lithium-ion batteries require efficient and stable solid-state electrolytes.
• Lanthanum zirconate-based materials are candidates for solid electrolytes.
• Niobium substitution can influence the structural and conductive properties of these materials.

Purpose of the Study:

• To grow a high-quality single crystal of niobium-substituted lithium lanthanum zirconium oxide (Li$_{6.95}$La$_{3}$Zr$_{1.95}$Nb$_{0.05}$O$_{12}$).
• To determine the crystal structure and lattice parameters of the synthesized material.
• To evaluate the bulk lithium-ion conductivity of the single crystal.

Main Methods:

• Single-crystal growth using the floating zone method.
• Single-crystal X-ray diffraction for structural determination.
• Conductivity measurements at room temperature (298 K).

Main Results:

• A single-crystal rod of Li$_{6.95}$La$_{3}$Zr$_{1.95}$Nb$_{0.05}$O$_{12}$ was successfully grown.
• The crystal structure was determined to be orthorhombic (space group *Ibca*) with precise lattice parameters.
• The bulk lithium-ion conductivity was measured to be 3.21 × 10$^{-4}$ S cm$^{-1}$ at 298 K.

Conclusions:

• The synthesized Li$_{6.95}$La$_{3}$Zr$_{1.95}$Nb$_{0.05}$O$_{12}$ single crystal possesses a well-defined orthorhombic structure.
• The material demonstrates significant lithium-ion conductivity at room temperature.
• This niobium-substituted compound shows potential as a solid electrolyte material.