A cheaper and more sustainable LiDFOB electrolyte reduces lithium salts while maintaining battery performance.

An international research team has developed an electrolyte with a very low concentration of lithium salt for a cheaper, safer alternative to conventional lithium batteries.

According to the report, battery cells using these LiDFOB – lithium difluoro (oxalato) borate – electrolytes in batteries with standard electrodes have demonstrated outstanding performance, promising sustainability with simplified production and recycling processes.

The main components of most lithium-ion (Li-ion) batteries are lithium cobalt oxide (LCO) cathodes, graphite anodes, and liquid electrolyte carrying electrons between the two. Standard commercial electrolytes, however, are still mostly based on a system formulated over 30 years ago.

Over the past decade, there have been significant advancements in high-concentration electrolytes whose power gains have come at the price of high viscosity, limited wetting capability, and inferior conductivity. With a reliance on large quantities of lithium salts, today's Li-ion battery production gobbles up the highly reactive silvery-white mineral, leaving them prohibitively expensive.

A new chemistry

A team of University of Puerto Rico-Rio Piedras Campus and Ningbo University researchers led by Jinliang Yuan, Lan Xia, and Xianyong Wu have developed an ultralow-concentration LiDFOB electrolyte that could be substituted in lithium-ion batteries without requiring a full redesign.

LiDFOB production would require no strict dry room conditions, be water- and air-stable, and make end-of-life battery recycling significantly easier and cheaper.

The electrolyte would serve as a cost-effective alternative to more common chemistries. Paired with ethylene carbonate (EC) and dimethyl carbonate (DMC), this electrolyte achieves an impressively high ionic conductivity, rendering it viable for battery operation with outstanding cycling performance and stability and marking a significant advancement in battery technology.

"This electrolyte exhibits a record-low salt/solvent mass ratio reported to date, thus pointing to a superior low cost," the report said. "Furthermore, this electrolyte is highly compatible with commercial Li-ion materials, forming stable and inorganic-rich interphases on the lithium cobalt oxide (LiCoO2) cathode and graphite anode."

Electrolytes in current use decompose in the presence of moisture, releasing highly toxic and corrosive hydrogen fluoride gas. The report emphasized this new formulation "is moisture-resistant and effectively suppresses the generation of hydrogen fluoride, which will markedly facilitate the battery assembly and recycling process under ambient conditions."

The published study was funded by the National Natural Science Foundation of China, the Zhejiang Provincial Natural Science Foundation of China, the Ningbo Science & Technology Innovation 2025 Major Project, and the NSF Center for the Advancement of Wearable Technologies.