UNIST Develops Solid-State Fluorination Reaction Technology ... Enhancing Lithium Battery Performance and Stability

A safe solid-state fluorination reaction technology that simultaneously achieves the performance, stability, and environmental benefits of lithium-ion battery anodes has been developed.

Professor Jongbeom Baek's team from the Department of Energy and Chemical Engineering at UNIST developed a method to safely and easily synthesize fluorinated carbon by reacting Teflon (PTFE) with graphite.

Using ball-milling, a representative mechanochemical reaction induction method, they confirmed a storage capacity and electrochemical stability more than 2.5 times superior to that of graphite.

The compounds required to produce fluorinated carbon, such as fluorine gas (F2) and hydrofluoric acid (HF), are highly reactive and corrosive, making them very dangerous. They can cause paralysis or death and increase the manufacturing facility costs for large-scale production.

The research team devised a fluorination method using solids to induce a safe and easy fluorination reaction.

Teflon, a compound commonly used in everyday life composed entirely of fluorine atoms, is a polymer compound that is stable in the atmosphere and harmless to the human body even if ingested.

The process of producing fluorocarbon through mechanochemical ball milling.

Used as a coating for frying pans, Teflon reduces surface friction and is chemically stable, so it is generally not used as a reactant.

In experiments, the research team confirmed that when Teflon is subjected to energy stronger than it can withstand, the molecular chains break, triggering a radical formation reaction.

They proved through various analytical methods that the molecular complexes formed in this process react with graphite, attaching to its surface and edges to form fluorinated carbon.

Fluorinated carbon produced by solid-state reaction showed superior storage capacity and electrochemical stability compared to graphite. At a low charging rate of 50 mA/g, it exhibited a 2.5 times higher storage capacity (951.6 mAh/g), and at a high charging rate of 10,000 mA/g, it showed up to 10 times higher storage capacity (329 mAh/g) than graphite.

In over 1,000 charge-discharge cycles conducted at a charging rate of 2,000 mA/g, graphite maintained 43.8% of its performance, whereas fluorinated carbon maintained a high performance of 76.6%.

Professor Jongbeom Baek of UNIST (left), first author researcher Bujae Jang.

Jang Bujae, the first author and a researcher in the Department of Energy and Chemical Engineering, emphasized, “Although this study was conducted under the theme of safe fluorination reactions, the most important aspect is that it suggests the direction and potential of solid-state reactions.”

He added, “Fluorinated carbon can be applied not only to secondary batteries but also to electrode materials for various electronic devices, enabling safe and easy large-scale production.”

Professor Jongbeom Baek of the Department of Energy and Chemical Engineering stated, “Mechanochemical synthesis has recently attracted attention to the extent of being featured in Science. If the principles of solid-state reactions are well elucidated, new materials that could not be made before can be developed.”

The research was conducted with support from the U-K Brand at Ulsan National Institute of Science and Technology, the Carbon Neutrality Committee, and the Ministry of Science and ICT and the National Research Foundation of Korea’s Leading Research Program.

The results of this study were published online on July 27 in the international journal Advanced Functional Materials in the fields of energy and materials.

This content was produced with the assistance of AI translation services.