This schematic diagram illustrates various causes and mechanisms of thermal runaway occurring in batteries. /Courtesy of Korea University

Professor Yoo Seung-ho's research team at Korea University has developed a technology to prevent battery thermal runaway.

The research team led by Professor Yoo announced on the 17th that they found a solution to enhance the safety of the existing organic electrolyte system using phosphorus-based flame-retardant additives, effectively suppressing thermal runaway, a major cause of battery explosions. The research results were published in the international journal 'Advanced Energy Materials' in March.

Concerns about the safety of lithium-ion batteries used in electric bicycles and electric scooters have been ongoing. One of the main causes of accidents is the thermal runaway phenomenon. Due to external shocks or overheating, the chemical reactions inside the battery accelerate, leading to self-ignition or explosions. Especially, the carbonate-based organic electrolytes used in lithium-ion batteries easily ignite at room temperature, becoming direct ignition factors.

To prevent this, active research on flame-retardant electrolytes that enhance battery stability is underway. However, the flame-retardant electrolytes developed so far are based on high-concentration fluorinated salts or introducing a large amount of fluorine atoms, resulting in high expenses and limitations in battery performance.

The research team utilized phosphorus-based flame-retardant additives. Phosphorus compounds effectively function with small amounts and produce less toxicity when combusted, making them advantageous for ensuring battery safety. Moreover, they have a minimal impact on the physical characteristics or electrochemical performance of the electrolyte, reducing concerns about battery performance degradation, and they are less expensive.

The research team systematically organized the structural characteristics and mechanisms of various phosphorus-based additives and presented the feasibility for practical application and material development directions. They derived practical solutions that dramatically enhance the safety and reliability of lithium batteries.

Professor Yoo said, "This research is a case that proves the possibility of designing additives that can simultaneously secure the flame retardancy and interfacial stability of batteries," and added, "Based on this, it is expected to contribute to the commercialization of next-generation battery systems by expanding the usability of phosphorus-based additives."

References

Advanced Energy Materials (2025), DOI: https://doi.org/10.1002/aenm.202500587

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