A research team at the Daegu Gyeongbuk Institute of Science and Technology (DGIST), South Korea, has announced a method to significantly enhance the stability of ultra-thin lithium metal anodes.
The team has successfully addressed long-standing issues of lifespan and safety that have hindered the widespread adoption of lithium metal batteries.
“This study focused on overcoming the limitations of ultra-thin lithium metal and significantly enhancing the stability of lithium metal batteries,” stated Professor Yu Jong-sung, who led the research team.
The researchers achieved this breakthrough by introducing a novel electrolyte additive, silver trifluoromethanesulfonate (AgCF₃SO₃, or AgTFMS), which facilitates the simultaneous formation of silver (Ag) and lithium fluoride (LiF) on the surface of the lithium metal anode.
This dual-layer protection effectively suppresses the formation of lithium dendrites, which are microscopic, finger-like structures.
“During charge-discharge cycles, lithium tends to grow in dendritic forms, causing short circuits and thermal runaway, which lead to lifetime and safety issues,” explained the team in a press release.
The team’s approach suppressed dendrite growth and mitigated electrolyte depletion caused by repeated degradation and reformation of the solid electrolyte interphase (SEI).
“By forming a high-performance SEI through a simple approach, we have developed a technology that improves both the lifetime and efficiency of lithium batteries,” explained Professor Yu.
Lithium metal anodes show an impressive energy storage capacity, over ten times that of conventional graphite anodes, which makes them highly desirable for powering future technologies like electric vehicles and advanced electronic devices.
However, their inherent instability, particularly in ultra-thin formats crucial for commercial viability, has been a major obstacle.
Focus on stabilizing 20μm anodes
Using ultra-thin lithium metal under 50μm is crucial for commercializing lithium metal batteries, but stability issues worsen as the thickness decreases.
“The use of ultra-thin lithium metal with a thickness below 50μm is essential, especially for the commercialization of lithium metal batteries. However, such issues become more severe as thickness reduces,” highlighted the researchers.
The team focused specifically on stabilizing anodes with a thickness of just 20μm, where instability issues are typically exacerbated.
Through rigorous surface analysis, they confirmed that the AgTFMS additive enabled the concurrent creation of a robust protective layer composed of both mechanically strong LiF and silver, which promotes uniform lithium deposition during charging.
“They successfully enhanced the stability of ultra-thin (20μm) lithium metal anodes and experimentally verified that dendrite formation could be effectively suppressed and the battery life could be extended by more than seven times compared to the conventional system,” remarked the press release.
Computational validation of mechanism
Complementing the experimental work, Professor Kang Jun-hee’s team at Pusan National University employed computational chemistry to analyze the interaction energy between lithium and silver.
Their findings revealed the underlying mechanism by which silver promotes more uniform lithium deposition, which further validated the effectiveness of the AgTFMS additive.
“We expect that this advancement will accelerate the commercialization of lithium metal batteries as sustainable energy storage systems across various applications, including electric vehicles, unmanned aerial vehicles, and ships,” concluded Prof. Yu.
