Solvent for solid electrolyte synthesis containing an onium salt compound using imidazolium cations, and a method for synthesizing a solid electrolyte using the same

High-Temperature Wet Synthesis Technology for Solid Electrolytes Using Low-Viscosity Imidazolium Ionic Liquid Solvents

This technology enables the wet synthesis of solid electrolytes by utilizing imidazolium cation-based onium salt compounds (ionic liquids) as solvents. It allows for stable solid electrolyte synthesis across a wide temperature range of 100–400°C.

Conventional dry processes for all-solid-state batteries have been limited by difficulties in scaling up. Even when wet processes are applied, uneven contact between the solid electrolyte and electrodes often leads to reduced capacity and performance.

This technology utilizes onium salt compounds composed of imidazolium cations and anions such as BF4-, NO3-, PF6-, and AsF6- as solvents to perform wet synthesis at 100–400°C. These solvents maintain a low viscosity of 4–6 cP at 100°C, ensuring excellent dispersibility, mitigating electrolyte leakage and short circuits, and enhancing high-temperature ionic conductivity. Applicable to the mass production of sulfide and oxide-based solid electrolytes, it overcomes the scale-up constraints of dry processes to enable large-area electrolyte manufacturing.

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Key Features:

• Synthesizing a solid electrolyte at a reaction temperature of 100 to 400 °C in a solvent containing an imidazolium salt compound
• An imidazolium salt compound solvent having at least one anion selected from BF4-, NO3-, PF6-, and AsF6-
• Preparing an imidazolium salt compound by stirring a salt compound and a sodium salt compound in an acetone solvent at 20 to 27 °C for 20 to 30 hours
• Preparing a salt compound by stirring a compound of Formula 5 and a compound of Formula 6 at -3 to 1 °C for 48 to 72 hours

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