Anion sublattice design enables superionic conductivity in crystalline oxyhalides

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Chemistry

Background:

• Solid-state batteries offer enhanced safety over conventional lithium-ion batteries.
• Development of solid-state electrolytes (SSEs) is crucial for advancing solid-state battery technology.
• Current SSEs are predominantly single-anion systems, limiting performance and design flexibility.

Purpose of the Study:

• To design and synthesize novel mixed-anion solid-state electrolytes.
• To investigate the ionic conductivity and electrochemical stability of these new materials.
• To evaluate their performance in solid-state battery applications.

Main Methods:

• Mixed-anion design strategy was employed to create crystalline Li3Ta3O4Cl10 (LTOC).
• Ionic conductivity measurements were performed at various temperatures.
• Electrochemical stability and compatibility with cathode materials were assessed.
• Li-ion migration pathways were analyzed based on structural features.

Main Results:

• Crystalline LTOC and its derivatives were successfully synthesized.
• Achieved high ionic conductivities up to 13.7 mS/cm at 25°C.
• Demonstrated excellent electrochemical stability up to 4.9 V vs. Li/Li+.
• LTOC exhibits continuous Li-ion migration pathways facilitated by mixed-anion spiral chains.
• Enabled solid-state battery operation from -50°C to elevated temperatures.

Conclusions:

• Mixed-anion design is a viable strategy for developing advanced SSEs.
• LTOC represents a promising superionic conductor for high-performance and safe solid-state batteries.
• The unique structural features of LTOC facilitate efficient Li-ion transport.