Flourine-free binder, electrolyte for greener batteries

A team of researchers from Pohang University of Science and Technology (POSTECH) have developed a new fluorine-free binder and electrolyte designed to advance eco-friendly, high-performance battery technology.

Growing environmental concerns have emphasised the importance of sustainable materials in battery technology. Traditional lithium batteries rely on fluorinated compounds such as polyvinylidene fluoride (PVDF) binders and lithium hexafluorophosphate (LiPF6, LP) salts. However, this “PVDF-LP” system releases toxic hydrogen fluoride, which reduces battery performance and lifespan. PVDF is also non-biodegradable, and with the European Union tightening the regulations on PFAS, a ban on these substances is expected by 2026.

The researchers from POSTECH have designed a non-fluorinated battery system to comply with upcoming environmental regulations and enhance battery performance. The researchers developed a lithium perchlorate-based electrolyte to replace fluorinated LP electrolytes along with a non-fluorinated aromatic polyamide (APA) binder. This “APA-LC” system is reportedly free of fluorinated compounds.

The APA binder reinforces the bonding between the cathode’s active material and the aluminium current collector, preventing electrode corrosion in the electrolyte and extending battery life. The LC system, enriched with lithium chloride and lithium oxide, lowers the energy barrier at the interface to promote ion migration, leading to faster lithium diffusion and enhanced output performance. Overall, the APA-LC system exhibited greater oxidation stability than the conventional PVDF-LP system and maintained 20% higher capacity retention after 200 cycles at a rapid charge/discharge rate of 1 C, within the 2.8–4.3 V range in a coin cell test.

The researchers applied the APA-LC system to produce a high-capacity Ah (ampere-hour) pouch cell. The cell maintained excellent discharge capacity and demonstrated strong performance during fast-charging trials. Professor Soojin Park of POSTECH said the researchers have not just replaced fluorinated systems; they 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,” Park said.

The research findings have been published in the Chemical Engineering Journal.

Image credit: iStock.com/Petmal