Thermal runaway suppressed by 90% with ionic compound
87% capacity retention at minus 20 degrees Celsius
Potential for expansion to all-solid-state and other applications
LG Energy Solution, in collaboration with Pohang University of Science and Technology (POSTECH) and Sungkyunkwan University, has developed a core electrolyte technology that simultaneously improves the low-temperature performance and thermal safety of lithium-ion batteries.
On October 20, LG Energy Solution announced that the research team confirmed the new electrolyte retained approximately 87% of its capacity after 100 charge-discharge cycles at minus 20 degrees Celsius, compared to conventional electrolytes, and suppressed thermal runaway by more than 90%. The results were published in the international energy journals "Advanced Energy Materials" and "Journal of Materials Chemistry A," respectively.
The core of this research lies in mixing a new ionic compound called allyl trimethyl phosphonium (APT) into the electrolyte. This compound prevents the electrolyte from freezing easily and stabilizes its reaction with the electrodes. As a result, ions can move efficiently even at subzero temperatures, maintaining performance. In fact, cells using this electrolyte retained about 87% of their initial capacity after 100 charge-discharge cycles at minus 20 degrees Celsius. This marks a significant improvement compared to conventional electrolytes, which retain only about 10% under the same conditions.
The research team also applied the same APT-based compound to high-capacity silicon anode batteries and succeeded in reducing thermal runaway by more than 90%. The heat generated when a cell catches fire was reduced to one-tenth of the previous level, significantly slowing the spread of heat to surrounding cells. The team explained that they were able to improve the thermal safety of high-energy-density batteries simply by changing the electrolyte composition, without altering the complex cell structure.
Professor Ki-ra Lee of the Department of Chemical Engineering at Pohang University of Science and Technology (left) and Professor Hoseok Park of the Department of Chemical Engineering at Sungkyunkwan University
LG Energy Solution stated that this research is the result of industry-academia collaboration, combining its own cell manufacturing and analysis capabilities, POSTECH's ionic compound synthesis technology, and Sungkyunkwan University's interfacial analysis expertise. Professor Ki-ra Lee's research team at POSTECH described it as "a model case of industry-academia cooperation, in which technical challenges from the industrial field were academically reinterpreted and developed into practical solutions." Professor Hoseok Park's team at Sungkyunkwan University explained, "By leveraging the molecular design flexibility of APT-based compounds, it is possible to expand to all-solid-state batteries and lithium metal batteries."
The research team expects this technology to be extended to various fields, including special-purpose batteries that operate in extremely low temperatures and next-generation batteries based on high-capacity silicon anodes. An LG Energy Solution representative stated, "This is a case where conflicting challenges of performance and safety have been solved with a single ionic compound platform," adding that "it can be utilized in a wide range of fields, including not only electric vehicles but also aviation and aerospace."
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