Clean Synthesis of Oxide Electrolytes via a Boiling Water-Assisted Solid-Phase Sintering Route

Area of Science:

• Materials Science
• Solid-state Chemistry
• Electrochemistry

Background:

• Solid-phase sintering (SS) is a common oxide synthesis technique but uses polluting organic liquids.
• Conventional SS methods incur higher costs and environmental concerns due to organic grinding media.

Purpose of the Study:

• To develop an environmentally friendly and cost-effective solid-phase sintering method for oxide materials.
• To demonstrate the efficacy of using water as a grinding medium in solid-phase sintering.

Main Methods:

• A novel boiling water-assisted solid-phase sintering (BWA-SS) process was developed using water as the grinding medium.
• Finite element analysis was employed to understand particle dispersion dynamics in boiling water.
• The BWA-SS method was applied to synthesize lithium lanthanum zirconium oxide (LLZO) and other oxide materials.

Main Results:

• The BWA-SS method successfully synthesized pure LLZO solid electrolyte with ionic conductivity (σᵢ) of 6.22 × 10⁻⁴ S/cm, comparable to conventional SS.
• A Li/LLZO/Li symmetrical cell demonstrated stable cycling for 3000 hours at 0.1 mA/cm².
• The method was validated for synthesizing other solid electrolytes (LTPO) and cathode materials (NCM811).

Conclusions:

• Boiling water-assisted solid-phase sintering offers a clean, scalable, and effective route for synthesizing various oxide materials.
• This organic-free approach mitigates environmental pollution and cost associated with traditional SS methods.
• The developed BWA-SS technique shows significant potential for the sustainable production of advanced oxide materials for energy applications.