Lithium-Ion Battery Separator Coated with Fluoropolymer Imparts Self-Extinguishing Ability
Published in International Journal ‘Journal of Materials Chemistry A’ and Selected as Cover Paper
The research team led by Professor Jo Gye-yong (majoring in Industrial Chemistry) at Pukyong National University has developed a separator that suppresses the ‘thermal runaway’ of lithium-ion secondary batteries used in electric vehicles.
Research team led by Professor Jo Gye-yong (from left: Professor Jo Gye-yong, Park Jae-won, Kwon Young-je, Kim Se-hoon, Bae Ji-woo, Lee Min-jung, Professor Yoon Jung-sik).
The research team, consisting of Professor Jo Gye-yong from Pukyong National University, master's researcher Park Jae-won, doctoral candidate Kwon Young-je, and Professor Yoon Jung-sik from Incheon National University (Department of Energy Chemical Engineering), developed a separator that improves the thermal stability of lithium-ion batteries and suppresses flames by introducing self-extinguishing capability.
The team developed this separator by coating a functionalized fluorine-based polymer onto a commercial polypropylene separator and utilizing a cross-linking reaction (a reaction that creates new chemical bonds in natural or synthetic polymers with chain-like structures to form a three-dimensional network structure).
Recently, to reduce carbon emissions, the development of hydrogen fuel cells and lithium-ion battery-based mobility devices has been progressing; however, lithium-ion battery-based electric vehicles have raised safety concerns due to thermal runaway phenomena such as ignition of organic electrolytes.
The lithium-ion secondary battery separator developed by Professor Jo Gye-yong’s research team is expected to suppress such thermal runaway phenomena by not only enhancing thermal stability but also possessing self-extinguishing ability.
The fluorine-based polymer coating layer suppresses thermal shrinkage of the separator at high temperatures through polymer cross-linking, thereby improving the separator’s high-temperature safety characteristics. During combustion, the electrolyte and coating layer of the separator decompose together, exhibiting self-extinguishing ability by continuously suppressing ignition through a catalytic combustion suppression effect when battery fires occur.
Park Jae-won, the first author of the paper, said, “This research not only alleviates safety concerns regarding lithium-ion batteries but also hopes that lithium-ion batteries will be used in more diverse fields for an eco-friendly future.”
Schematic image of self-extinguishing and internal short-circuit suppression of the separator through functionalized fluoropolymer coating.
This research was conducted with support from the Local Government-University Cooperation-Based Regional Innovation Project (RIS), the Ministry of Trade, Industry and Energy, and the Excellent New Researcher Project of the National Research Foundation. The paper titled ‘Fluorine-rich modification of self-extinguishable lithium-ion battery separators using cross-linking networks of chemically functionalized PVDF terpolymers for highly enhanced electrolyte affinity and thermal-mechanical stability’ was published on January 28 in an international journal (IF 11.9 / JCR top 8.8%) and was also selected as a cover paper.
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