DGIST develops lithium-metal battery that self-extinguishes in fires

A research team at the Daegu Gyeongbuk Institute of Science and Technology (DGIST) in South Korea has created a lithium-metal battery (distinct from the more common lithium-ion type) that not only lasts longer, but can also self-extinguish if a fire breaks out.

Researchers currently face a range of issues with conventional batteries, from weaker performance through to problems such as dendrites, which are a leading cause of unwanted fires.

To tackle this, the team led by Professor Lee Jung-ho and Dr Kim Jae-hyun set out to build a battery based on a “three-layer polymer solid electrolyte”. The idea is for each electrolyte layer to serve a different purpose, in order to markedly improve both safety and efficiency.

In this design, the middle layer is intended to provide greater heat resistance, while the outer layers make it easier for lithium ions to move, helping heat to dissipate.

According to the project leads, this structure “allows an increase in energy transfer rates, which effectively prevents dendrite formation”.

Dendrites appear when “there isn’t time for the lithium to diffuse easily to where it needs to go, so it remains «at the door»”, leading to messy, disorganised deposits.

DGIST lithium-metal battery design and materials

However, the layered architecture is not the only key element. The electrolyte in this battery also includes several specialised ingredients: Decabromodiphenyl ethane (DBDPE), a flame-retardant additive that helps prevent fires; zeolite, used to increase the electrolyte’s strength; and a high concentration of lithium salt (LiTFSI), “to enable fast ion movement”.

Early tests

After 1,000 charge–discharge cycles, the new battery retained around 87.9% of its performance, which is unusual. In comparison, conventional batteries typically keep only 70%–80% of performance after the same level of use.

In an electric car with a 500 km range (WLTP cycle), that would mean that after 500,000 km driven, the battery could still deliver a range of up to 439 km.

Potential applications beyond cars

These batteries are expected to be suitable not only for vehicles, but also for smartphones and large-scale energy storage systems.

“It is hoped that this research will make a significant contribution to the commercialisation of lithium batteries using (solid polymer) electrolytes, while also providing greater stability and efficiency for energy storage devices.”

Dr Kim Jae-hyun

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