Gel-type polymer electrolyte membrane and manufacturing method thereof

Self-supporting gel polymer electrolyte membrane for lithium batteries based on PEG-polyvinylpyridine triblock copolymers

This technology involves creating a gel-type polymer electrolyte membrane using a triblock copolymer that features an ethylene oxide chain in the center of the backbone, flanked by 4-vinylpyridine blocks, for application in lithium secondary batteries. The polymer is synthesized by coupling a RAFT initiator with PEG, followed by monomer polymerization.

Research has been ongoing to replace liquid electrolytes with polymer electrolytes to address safety concerns in lithium secondary batteries. However, conventional polymer electrolytes have required separate supports, such as PVdF-HFP, and have faced limitations in simultaneously improving mechanical properties and ionic conductivity.

In this technology, the ethylene oxide in the backbone forms channels for lithium-ion transport, while the block structure enhances mechanical strength, ensuring both high ionic conductivity and robust physical properties without the need for a support. Membrane quality is stabilized through a three-stage drying process with incremental temperature increases. This technology can be applied to lithium secondary batteries for electric vehicles and energy storage systems, enabling the design of highly safe electrolytes with reduced risks of leakage and ignition.

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Key Features:

• A triblock copolymer for polymer electrolytes comprising repeating units of Formula 3, where m' and l' are between 120 and 170
• A step of preparing a copolymer of Formula 4 by coupling 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid and PEG with DMAP and DCC
• A step of synthesizing a triblock copolymer by mixing the prepared copolymer with 4-vinylpyridine monomer in a 1:300 molar ratio, followed by the introduction of ion-exchange functional groups
• A step of completing the electrolyte membrane for lithium secondary batteries by drying the polymer membrane in three stages, sequentially increasing the temperature from 30–50℃ to 50–70℃, and finally to 70–90℃

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This invention was developed with support from the Ministry of Education for the development of blue carbon biomass-based source materials and the establishment of a marine resource recycling platform.

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