Fluorine-Free Battery System Demonstrates High Capacity and Stability

An international group of researchers from POSTECH, in collaboration with Hansol Chemical's Battery Materials R&D Center, has developed a new fluorine-free electrolyte and binder to enhance high-performance and eco-friendly battery technology. The findings were published in the Chemical Engineering Journal.

As environmental concerns grow, sustainable materials are becoming increasingly important in battery technology. Traditional lithium batteries use fluorinated substances like lithium hexafluorophosphate (LiPF₆, LP) salts and polyvinylidene fluoride (PVDF) binders. However, these materials release toxic hydrogen fluoride (HF), which degrades battery performance and lifespan. Additionally, PVDF is non-biodegradable, and the European Union (EU) is expected to ban these compounds by 2026 due to stricter PFAS regulations.

To address these issues, researchers from POSTECH and Hansol Chemical have developed a non-fluorinated battery system that enhances performance while complying with upcoming environmental regulations. Using Hansol Chemical's patented technology, they created a lithium perchlorate (LiClO₄, LC)-based electrolyte to replace the fluorinated LP electrolytes and combined it with a non-fluorinated aromatic polyamide (APA) binder. The resulting “APA-LC” system is completely free of fluorinated substances.

The "APA binder" significantly extends battery life by strengthening the bond between the cathode's active material and the aluminum current collector, thereby preventing electrode corrosion in the electrolyte. Additionally, the "LC system," enhanced with lithium oxide (Li₂O) and lithium chloride (LiCl), reduces the energy barrier at the interface, facilitating ion migration, speeding up lithium diffusion, and improving output performance compared to the current LP system.

In a coin cell test, the APA-LC system showed 20 % higher capacity retention after 200 cycles at a fast charge/discharge rate of 1 C, within the voltage range of 2.8–4.3 V, demonstrating superior oxidation stability over the traditional PVDF-LP system.

Using the APA-LC technology, the research team developed a high-capacity 1.5 Ah pouch cell that maintained strong performance and excellent discharge capacity during fast-charging tests. This is the first successful demonstration of a fully scalable and practical battery system that is entirely free of fluorinated compounds.

We have not just replaced fluorinated systems; we have proven high-capacity retention and outstanding stability. Our solution will advance the sustainability of the battery industry, facilitating the shift to non-fluorinated battery systems while ensuring environmental compliance.

Soojin Park, Professor,  Pohang University of Science and Technology

Young-Ho Yoon, Managing Director of Hansol Chemical’s Secondary Battery Materials Business, said, “By addressing PFAS regulatory concerns, we have secured a foothold in the global cathode binder market, projected to reach KRW 1.7 trillion by 2026. Continued research will solidify our position as a leading supplier of eco-friendly secondary battery materials.”

Journal Reference:

Nam, S., et al. (2024) All fluorine-free lithium-ion batteries with high-rate capability. Chemical Engineering Journal. doi.org/10.1016/j.cej.2024.154790.