Method for Manufacturing Free-Standing Solid Electrolyte Composite Sheet and All-Solid-State Battery Equipped with the Same

Large-Area Dense Solid Electrolyte Sheet Based on Release Film Sandwich Compression Process

This technology manufactures dense, large-area, free-standing solid electrolyte sheets by placing a slurry containing a solid electrolyte and a binder between two release films to create a laminate, which is then compressed and dried.

Conventional methods struggle to control internal voids and face limitations in scaling up due to the constraints of high-temperature pressing processes. Additionally, increasing the binder content often leads to a reduction in ionic conductivity.

This technology forms a laminate by coating slurry between release films and compressing it at 0.1–1000 MPa to increase sheet density, while the release films block external moisture and facilitate easy peeling. As a result, it can be applied to roll-to-roll production of sulfide-based all-solid-state battery electrolyte membranes and large pouch-cell assembly, enabling the stable production of thin, wide electrolyte layers without the need for a support structure.

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Key Features:

• Preparing a solid electrolyte composite slurry using a mixture containing a solid electrolyte, a binder, and a solvent
• Coating the slurry onto one side of a release film and placing another release film on top to form a laminate
• Compressing the laminate with the solid electrolyte composite slurry sandwiched between the two release films to achieve a large area
• Peeling the release films from the compressed laminate to produce a free-standing solid electrolyte composite sheet

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of manufacturing technology for solid electrolyte membranes with an ionic conductivity of 1 mS/cm or higher and a thickness of 30 μm or less.

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