A research group led by Professor Yu Seung-ho from the Department of Chemical and Biological Engineering at KU (President Kim Dong-Won) conducted a joint study with Professor Sung Yung-eun’s group from Seoul National University and elucidated the interfacial stabilization mechanism of the electrolyte additive TDFA to address the issue of limited lifespan in lithium metal batteries.
Lithium metal batteries are drawing much attention as a next-generation energy storage technology because their theoretical capacity is ten times more than that of conventional lithium-ion batteries, potentially overcoming current energy density limitations. However, repeated charging and discharging often results in uneven lithium deposition, leading to surface instability and ultimately reducing battery capacity and shortening the battery’s overall lifespan.
To solve these problems, the joint research team analyzed the effects of the additive TDFA, which contains both fluorine and silicon, on the solid electrolyte interphase (SEI) formation and the solvation structure. The results showed that TDFA is preferentially reduced in the electrolyte and that the formation of a lithium fluoride (LiF)-rich SEI layer occurs spontaneously. In addition, the researchers conducted simulations and microscopic analyses, further revealing that ion mobility was improved and that lithium was deposited more uniformly in environments with TDFA.
The joint research team demonstrated that TDFA suppresses dendrite formation and forms a stable interface, thereby playing a crucial role in improving battery lifespan and charging efficiency. This study is significant because it precisely revealed how additives function at the lithium metal interface and thus presented an important direction for establishing interfacial design strategies in order to commercialize next-generation lithium metal batteries.
KU Professor Yu Seung-ho said, “For the commercialization of lithium metal batteries, ensuring the interfacial stability and controlling lithium deposition are essential. By elucidating the mechanism of SEI control using additives through this study, we will be able to contribute to the realization of next-generation high-energy density batteries in the future.”
This study was supported by the Ministry of Science and ICT and the National Research Foundation of Korea.