Tailor-made development of fast Li ion conducting garnet-like solid electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Solid lithium ion electrolytes are crucial for advanced energy storage and ionic devices.
• Garnet-family compounds are known for fast lithium ion conduction.
• Designing novel electrolytes with enhanced properties remains a key challenge.

Purpose of the Study:

• To develop advanced solid lithium ion electrolytes via a novel solid-solution reaction.
• To investigate the structure-property relationships in garnet-type electrolytes.
• To explore potential applications in solid-state ionic devices.

Main Methods:

• Solid-solution reaction between Li(6)BaLa(2)M(2)O(12) (M=Nb, Ta) and Li(7)La(3)Zr(2)O(12).
• Characterization using Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), AC impedance, and (7)Li Nuclear Magnetic Resonance (Li NMR) spectroscopy.
• Analysis of phase formation, morphology, ionic conductivity, and Li ion coordination.

Main Results:

• Formation of a cubic garnet-like structure in Li(6.5)La(2.5)BaZrMO(12).
• Li(6.5)La(2.5)BaZrTaO(12) achieved a conductivity of 6 x 10(-3) S cm(-1) at 100°C.
• Optimized sintering at 1100°C yielded higher electrical conductivity.
• (7)Li MAS NMR indicated fast ion migration and octahedral coordination.

Conclusions:

• A novel solid-solution approach successfully produced garnet-type lithium ion electrolytes.
• The Ta-based garnet exhibits competitive ionic conductivity for solid-state applications.
• Established fundamental relationships between properties, composition, and structure in garnet electrolytes.