"Operates at Minus 20 Degrees"...DGIST Develops Next-Generation Battery with Lower Fire Risk [Reading Science]

Development of Flame-Retardant Solid Electrolyte
Promising Solution for Improving Electric Vehicle Performance in Winter

The research team at Daegu Gyeongbuk Institute of Science and Technology (DGIST) has developed a next-generation solid electrolyte technology for batteries that operates stably even in subzero temperatures while significantly reducing the risk of fire. This technology is drawing attention for its potential to simultaneously address the winter performance degradation and fire hazards associated with electric vehicle batteries.

(Top left) Illustration showing the principle of enhancing lithium-ion mobility at low temperatures through the interaction between polymer electrolyte and fluorine-based additives. (Bottom left) Conceptual diagram of fluorine-based additives stabilizing the polymer structure to reduce electrolyte decomposition even under high-voltage conditions. (Right) Illustration depicting the structure and operating principle of lithium metal solid-state batteries that simultaneously improve flame retardancy and low-temperature performance. Provided by the research team

On May 7, DGIST announced that the research team led by Jaehyun Kim, Principal Researcher at the Energy and Environment Research Division, has developed a polymer solid electrolyte for lithium metal batteries that maintains high performance even at low temperatures. This study was conducted in collaboration with the research team of Professor Sangwook Lee at Sungkyunkwan University and Professor Sang-Eun Jeon at Kyungpook National University. The results have been published in the international journal Energy Storage Materials.

Lithium metal batteries are considered next-generation batteries because they offer higher energy density than conventional lithium-ion batteries. However, when using liquid electrolytes, the growth of lithium dendrites inside the battery leads to fire hazards and a reduction in battery lifespan. Although research on solid electrolytes has been ongoing to address these issues, conventional polymer-based solid electrolytes have had problems with a sharp decline in performance at low temperatures and low stability in high-voltage environments.

The research team addressed these challenges by developing a new solid electrolyte structure using fluorine-based additives, which prevents freezing at low temperatures and enhances flame retardancy. The key achievement is the stabilization of the polymer structure, which increases lithium-ion mobility and enables stable operation even in cold environments.

Research team led by Jaehyun Kim, Principal Researcher at the Energy and Environment Research Department of DGIST (far right in the back row).

The developed electrolyte maintained high ionic conductivity even at temperatures below minus 20 degrees Celsius, suppressed the growth of lithium dendrites, and improved battery lifespan characteristics. Notably, its flame-retardant properties were confirmed to reduce the risk of fire.

The team also explained that they validated the compatibility with existing liquid battery manufacturing methods by applying a process to form polymers inside the cell. There is an expectation that, following further safety verification, this technology could be commercialized for real-world battery applications.

Jaehyun Kim, Principal Researcher, stated, "This research demonstrates polymer solid electrolyte technology that ensures stability and safety even in low-temperature environments," adding, "We expect it to serve as a foundational technology for the development of next-generation high-energy-density batteries."

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