Organic-inorganic composite electrolyte membrane and manufacturing method thereof

Flexible thin-film electrolyte featuring a sulfide and solvate ionic liquid photocured into a porous scaffold

This technology addresses the brittleness and interfacial instability of sulfide-based solid electrolytes. By impregnating a porous scaffold with a specific pore size with a sulfide-based solid electrolyte, a cross-linked polymer matrix, and a lithium salt-coordinated solvate ionic liquid, it achieves flexibility and creates continuous ion-conduction pathways between inorganic particles.

While sulfide-based solid electrolytes offer high ionic conductivity, their rigid and brittle nature makes them difficult to manufacture as thin films and limits their flexibility. Furthermore, they face challenges such as high interfacial resistance with electrodes and susceptibility to dendrite growth.

This technology involves applying a solvent-free slurry—composed of a sulfide-based solid electrolyte, a multifunctional monomer for a cross-linked polymer matrix, a solvate ionic liquid, and a lithium salt—onto a porous scaffold with an average pore size of 50㎛ or larger, followed by photocuring to create an integrated composite membrane. Suitable for flexible all-solid-state batteries and thin power sources for wearable devices, this technology provides electrolyte membranes thinner than 40㎛ that retain over 90% of their ionic conductivity even after 100 cycles of 180° bending.

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Key Features:

• Porous scaffold with an average pore size of 50㎛ or larger and a thickness of 5 to 40㎛
• Organic-inorganic composite electrolyte integrated with a porous scaffold, containing only sulfide-based solid electrolyte as the solid electrolyte
• Cross-linked polymer matrix derived from multifunctional monomers containing two or more photocurable functional groups, included at 0.5 to 10 parts by weight per 100 parts by weight of the sulfide-based solid electrolyte
• Solvate ionic liquid containing a glyme-based solvent and a lithium salt in a molar ratio of 0.5 to 1.5:1

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This invention was developed with support from the Ministry of Science and ICT for a single-ion conductor-based multidimensional free-form power system.

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