Preparation of thin solid electrolyte by hot-pressing and diamond wire slicing

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Chemistry

Background:

• Solid electrolyte thickness critically impacts all-solid-state battery performance, with thicker electrolytes increasing impedance.
• Thin solid electrolytes are essential for improving battery performance by shortening Li ion diffusion paths and reducing volume.

Purpose of the Study:

• To prepare thin Li1.5Ge1.5Al0.5(PO4)3 solid electrolytes using diamond wire slicing.
• To evaluate the effectiveness of diamond wire slicing as a fabrication technique for thin solid electrolytes.

Main Methods:

• Melt-quenching of Li1.5Ge1.5Al0.5(PO4)3 followed by crystallization at 800 °C for 8 hours.
• Fabrication of a Li1.5Ge1.5Al0.5(PO4)3 rod.
• Thinning the crystallized rod to 200 μm using diamond wire slicing.

Main Results:

• A thin Li1.5Ge1.5Al0.5(PO4)3 solid electrolyte of 200 μm thickness was successfully prepared without altering crystal structure or morphology.
• The thin electrolyte exhibited a total Li conductivity of 3.3 × 10⁻⁴ S cm⁻¹ and an activation energy of 0.32 eV.
• The ionic transference number was measured to be 0.999, indicating excellent Li ion transport.

Conclusions:

• Diamond wire slicing is a viable and efficient method for preparing thin solid electrolytes.
• The prepared thin Li1.5Ge1.5Al0.5(PO4)3 electrolyte shows comparable performance to materials fabricated via tape-casting, but with a simpler process.
• This technique facilitates the development of high-performance all-solid-state batteries.