A research team from the Division of Energy & Environmental Technology at DGIST, led by Principal Researcher Kim Jae-hyun, has developed an innovative lithium metal battery featuring a “triple-layer solid polymer electrolyte.” This advancement promises significant improvements in both fire safety and battery lifespan, positioning it as a potential game-changer for applications in electric vehicles and large-scale energy storage systems.

Traditional solid polymer electrolyte (SPE) batteries have faced persistent challenges, particularly in ensuring optimal contact between the battery’s electrodes. This is critical in preventing the formation of “dendrites”—tree-like structures of lithium that form during repeated charging and discharging cycles. These dendrites can cause internal short circuits, potentially leading to fires or even explosions, posing a significant safety hazard.

To address these issues, the DGIST research team developed a unique triple-layer structure for the solid polymer electrolyte, with each layer serving a specific function to improve the battery’s performance. The design incorporates decabromodiphenyl ethane (DBDPE), a fire-retardant compound that helps prevent fires, zeolite to enhance the mechanical strength of the electrolyte, and a high concentration of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), which accelerates the movement of lithium ions through the electrolyte.

The triple-layer structure features a robust middle layer that bolsters the battery’s mechanical strength, while the soft outer layer ensures excellent electrode contact, allowing for the efficient movement of lithium ions. This combination facilitates faster ion movement, preventing the dangerous formation of dendrites and improving overall battery efficiency.

Experimental tests on the new battery showed promising results, with the battery retaining about 87.9% of its capacity after 1,000 charging and discharging cycles. This marks a significant improvement in longevity compared to traditional lithium batteries, which typically retain only 70–80% of their capacity after the same number of cycles. Additionally, the new battery has self-extinguishing properties, significantly reducing the risk of fires—a critical safety enhancement.

The successful performance of this lithium metal battery paves the way for its use in a variety of sectors, ranging from small consumer electronics like smartphones and wearables to larger-scale applications such as electric vehicles and energy storage systems. Dr. Kim Jae-hyun emphasized that this breakthrough research could play a key role in advancing the commercialization of lithium metal batteries, offering greater stability and efficiency for energy storage technologies.

The research was supported by the Future Materials Discovery Project (led by Professor Lee Jung-ho of Hanyang University) and the Mid-Career Researcher Program (led by Dr. Kim Jae-hyun) of the National Research Foundation of Korea.

For more details, the study titled “Triple-Layered Noncombustible PEO-Based Solid Electrolyte for Highly Safe Lithium-Metal Batteries” was published in Small on November 3, 2024, by Heesoo Lim, Munseok S. Chae, Hasan Jamal, Firoz Khan, Injun Jeon, Jongmin Kim, and Jae Hyun Kim. DOI: 10.1002/smll.202406200

This new development is expected to play a crucial role in the future of safer, more durable batteries for a wide range of applications, from personal devices to electric transportation and renewable energy storage solutions.

By Impact Lab