A research team from DGIST's (President Kunwoo Lee) Division of Energy & Environmental Technology, led by Principal Researcher Kim Jae-hyun, has developed a lithium metal battery using a "triple-layer solid polymer electrolyte" that offers greatly enhanced fire safety and an extended lifespan. This research holds promise for diverse applications, including in electric vehicles and large-scale energy storage systems.
Conventional solid polymer electrolyte batteries perform poorly due to structural limitations which hinder an optimal electrode contact. This could not eliminate the issue of "dendrites" either, where lithium grows in tree-like structures during repeated charging and discharging cycles. Dendrites are a critical issue, as an irregular lithium growth can disrupt battery connections, potentially causing fires and explosions.
The research team, therefore, developed a triple-layer structure for the electrolyte to address such issues. Each layer serves a distinct function, significantly enhancing the battery's safety and efficiency. This electrolyte incorporates "decabromodiphenyl ethane (DBDPE)" to prevent fires, "zeolite" to enhance the electrolyte's strength, and a high concentration of a lithium salt, "lithium bis (trifluoromethanesulfonyl) imide) (LiTFSI)," to facilitate a rapid movement of lithium ions.
The triple-layer solid electrolyte features a robust middle layer that boosts the battery's mechanical strength, while its soft outer surface ensures an excellent electrode contact, facilitating an easy movement of lithium ions. This enables a faster movement of lithium ions, enhancing energy transfer rates and preventing dendrite formation effectively.
The experiment showed that the battery developed by the research team retained about 87.9% of its performance after 1,000 charging and discharging cycles, demonstrating a notable improvement in durability compared with traditional batteries, which typically maintain 70-80% of their performance. It can also extinguish itself in a fire, thus significantly reducing the fire risk. This battery is expected to be applicable across various sectors, ranging from small devices like smartphones and wearables to electric vehicles and large-scale energy storage systems.
Dr. Kim stated, "This research is anticipated to make a significant contribution to the commercialization of lithium metal batteries using [solid polymer] electrolytes, while providing enhanced stability and efficiency [to] energy storage devices."
This study 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. The findings were published as the cover article in an international academic journal, Small, published by Wiley.
