The long-standing challenges of short lifespan and unstable interfaces that have hindered the commercialization of lithium metal batteries may soon be a thing of the past. The research teams of Professor Jinwoo Lee, Nam-Soon Choi from Korean researchers at Korea Advanced Institute of Science and Technology (KAIST) and Professor Tae Kyung Lee at Gyeongsang National University develop a new nanoparticle electrolyte designed specifically for high-speed charging/discharging and high-voltage lithium metal batteries.

Lithium metal batteries have garnered attention as next-generation energy storage solutions due to their high theoretical capacity and energy density. However, in real-world applications, their lifespan is significantly reduced due to electrolyte decomposition and dendritic lithium growth. Particularly in high-voltage environments, hydrogen fluoride (HF), a by-product of electrolyte decomposition, causes severe corrosion at the cathode and the solid electrolyte interface (SEI), compromising electrode structure and performance.

To tackle these issues, the researchers added nano-sized silicon nitride (Si3N4) particles to the electrolyte, enabling precise control over the lithium-ion solvation structure and promoting the formation of a robust, inorganic-rich SEI layer. These nanoparticles also effectively scavenge corrosive HF, significantly reducing cathode degradation and enhancing interface stability even under extreme conditions.

As a result, lithium metal batteries incorporating the nanoparticle electrolyte maintained long-term cycling performance at 50°C, 1C charge/discharge rate, and 4.5V. Notably, a pouch cell with an energy density of 360 Wh/kg retained 74% of its capacity even after 100 cycles, providing compelling evidence for the commercial viability of the nanoparticle additive.

Professor Lee Jinwoo said, “This study not only introduces a new electrolyte material but also comprehensively elucidates the operating mechanism of nanoparticle additives in lithium metal batteries,” and added “We expect it to serve as valuable foundational data for future research on the design and optimization of next-generation electrolytes.”

Operating Mechanism of Nano Silicon Nitride Additives in Lithium Metal Batteries. Reprinted with permission. Energy & Environmental Science, 10.1039/d4ee03862b

[Reference] Kim et al., (2025) “Concurrent electrode–electrolyte interfaces engineering via nano-Si3N4 additive for high-rate, high-voltage lithium metal batteries”, Energy & Environmental Energy, 10.1039/d4ee03862b

[Main Author] Jinuk Kim (KAIST), Dong Gyu Lee (Gyeongsang National University), Ju Hyun Lee (KAIST), Saehun Kim (KAIST)

Jinwoo Lee (KAIST), Tae Kyung Lee (Gyeongsang National University), Nam-Soon Choi (KAIST)

* Contact : Professor Jinwoo Lee jwlee1@kaist.ac.kr