Synergized Tricomponent All-Inorganics Solid Electrolyte for Highly Stable Solid-State Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) exhibits excellent ionic conductivity and Li metal compatibility.
• However, LLZTO requires high-temperature sintering, leading to high costs, poor mechanical properties, and interfacial resistance.

Purpose of the Study:

• To develop a novel, low-temperature processed composite solid electrolyte (CSE) for enhanced solid-state battery performance.
• To investigate the electrochemical properties and stability of the LLZTO-4LiBH4/xLi3BN2H8 composite.

Main Methods:

• Preparation of a tricomponent CSE (LLZTO-4LiBH4/xLi3BN2H8) via ball milling and hand milling.
• Fabrication of green pellets by cold pressing and low-temperature heating (120°C).
• Electrochemical characterization using Li|Li symmetrical cells and Li|CSE|TiS2 full cells.

Main Results:

• The CSE achieved high room-temperature ionic conductivity (1.73 × 10-3 S cm-1 at 30°C) and an ultrahigh Li-ion transference number (0.9999).
• Li|Li symmetrical cells demonstrated stable cycling over 1600 hours with minimal overpotential (30 mV).
• Li|CSE|TiS2 full cells delivered a capacity of 201 mAh g-1 with excellent cyclability.

Conclusions:

• The developed composite solid electrolyte offers a promising low-temperature fabrication route for high-performance solid-state batteries.
• The synergistic effects of LLZTO, LiBH4, and Li3BN2H8 contribute to low porosity, high ionic conductivity, and good deformability.
• This CSE overcomes the limitations of traditional high-temperature sintered electrolytes, paving the way for cost-effective and efficient energy storage.