Mo-O Dual-Doped Argyrodite Electrolyte Enables Stable All-Solid-State Lithium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Sulfide solid electrolytes are crucial for all-solid-state lithium batteries due to high ionic conductivity and mechanical properties.
• Practical application is limited by poor moisture stability and lithium metal compatibility.
• Need for improved solid electrolyte materials for safer and more efficient batteries.

Purpose of the Study:

• To synthesize and characterize Mo-O dual-doped argyrodite sulfide electrolytes.
• To enhance moisture stability and electrochemical performance of solid electrolytes.
• To investigate interfacial properties and dendrite suppression for lithium metal batteries.

Main Methods:

• Synthesis of Li₆P_1-xMo_xS_5-3xO_3xCl_1+x sulfide electrolytes via doping.
• Optimization of dopant concentration and annealing temperature (570 °C).
• Electrochemical testing, including ionic conductivity measurements, cycling stability, and lithium plating/stripping.

Main Results:

• Optimized Li₆P_0.95Mo_0.05S_4.85O_0.15Cl_1.05 achieved ionic conductivity of 3.97 mS cm^-1.
• Reduced H₂S gas generation (0.58 cm^-3 g^-1) and improved air stability.
• Demonstrated superior interfacial compatibility, suppressed lithium dendrites (1.51 mA cm^-2 critical current density), and 5600h stable plating/stripping.
• Achieved 90.3% capacity retention after 1000 cycles in a LiCoO₂/electrolyte/Li battery.

Conclusions:

• Mo-O dual doping effectively enhances moisture stability and electrochemical properties of sulfide solid electrolytes.
• The optimized electrolyte shows excellent interfacial compatibility and dendrite suppression capabilities.
• These findings pave the way for practical, high-performance all-solid-state lithium batteries.