No more “burning and exploding batteries”? DGIST addresses low-temperature performance and fire risks

□ A research team led by Principal Researcher Kim Jaehyun from the Division of Energy and Environmental Research at DGIST (President Lee Kunwoo) has developed a solid electrolyte technology for lithium metal batteries that operates stably even at low temperatures while reducing fire risks. The research is expected to help improve both the safety and performance of batteries and contribute to the commercialization of high-energy-density batteries in the future.

□ The study was conducted jointly by DGIST Principal Researcher Kim Jaehyun, Professor Lee Sangwook’s team at Sungkyunkwan University, and Professor Jeon Sangeun from Kyungpook National University.

□ Owing to their high energy density, lithium metal batteries are gaining attention as next-generation batteries. However, when conventional liquid electrolytes are used, side reactions destabilize the interface and lead to the formation of lithium dendrites, causing fire risks and reducing battery life. To address these issues, solid electrolytes have been proposed as an alternative. However, polymer-based solid electrolytes have limitations, including a sharp decline in performance at low temperatures and low stability in high-voltage environments.

□ To overcome these limitations, the research team developed a new solid electrolyte by incorporating fluorinated ether (FE) into a PEGDME-based polymer network. In this process, molecular interactions between the polymer and the additive stabilized the structure and significantly improved performance compared with conventional systems.

□ As a result, the newly developed electrolyte maintained a high ionic conductivity of over 1.46 × 10⁻⁴ S/cm without freezing, even at temperatures below -20°C, while improving lithium-ion mobility and enhancing battery performance. The electrolyte was also found to form a stable protective layer on the electrode surface, which suppressed lithium dendrite growth and improved cycle life performance even in cells that used a high-voltage cathode. In particular, the electrolyte is notable for its flame-retardant properties, which further reduce the risk of fire.

□ This technology applies an in-situ process that forms the polymer inside the cell, making it compatible with existing liquid battery manufacturing processes. It also demonstrated performance at a level suitable for practical battery applications, confirming its potential for commercialization.

□ Principal Researcher Kim Jaehyun said, “This study presents a solid polymer electrolyte technology that operates stably even in low-temperature environments while also ensuring safety,” and added, “We expect it to serve as an important foundation for the development of next-generation high-energy-density batteries.”

□ Meanwhile, Jeon Injun, Associate Researcher at the Division of Energy and Environmental Research at DGIST, participated in the study as co-first author, while Senior Researcher Kim Jongmin participated as a co-author. The research was supported by the Mid-Career Researcher Program of the National Research Foundation of Korea (NRF), and the findings were published in April in the international journal Energy Storage Materials.