Manufacturing method for solid electrolyte powder for lithium secondary batteries

Solid electrolyte powder with uniform nano-oxide coating via rotary reactor atomic layer deposition

This technology uses an atomic layer deposition (ALD) process to uniformly form a 0.1–10nm thick metal oxide thin film on the surface of solid electrolyte powder for lithium secondary batteries. By utilizing periodic reactor rotation, stirring beads, and an injection induction pumping sequence, it prevents particle agglomeration and maximizes coating uniformity.

Conventional coating methods, such as the sol-gel process, struggle to control coating thickness and are prone to particle agglomeration and uneven coating. These limitations often result in reduced ionic conductivity and an inability to sufficiently suppress chemical side reactions at the electrode-electrolyte interface.

This technology features a rotatable reactor within a vacuum chamber where beads and powder are agitated together. It repeats the ALD cycle—consisting of coating source supply, purge, oxidant supply, and purge—while using injection induction pumping after each supply phase to prevent precursor backflow and precisely control hold, purge, and pumping times. Applicable to mass production of all-solid-state batteries using oxide-based solid electrolytes like garnet-type LLZO and powder surface modification equipment, it ensures uniform coating quality across the entire powder while suppressing interfacial side reactions with a nanometer-scale protective layer.

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Key Features:

• A reactor rotatably installed within a vacuum chamber, periodically rotated by a rotation unit to coat powder
• A step of performing multiple atomic layer deposition cycles by sequentially injecting coating source, purge gas, oxidant, and purge gas through a process gas supply unit
• An injection induction pumping step that induces injection into the reactor after blocking the coating source supply to prevent backflow of the coating source
• Stirring beads with a diameter of 0.01–1mm, added to the reactor at a weight ratio of 3:1 to 20:1 relative to the powder

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This invention was developed with support from the Ministry of Science, ICT and Future Planning's Research Center for Innovative Construction Structures.

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