Researchers describe a design for a self-extinguishing rechargeable battery in a newly-published study by Nature Sustainability.

It replaces the most commonly used electrolyte, which is highly combustible—a medium composed of a lithium salt and an organic solvent—with materials found in a commercial fire extinguisher: a fluorinated liquid and a non-polar solvent. This solution avoids using non-flammable organic solvents, which contain fluorine and phosphorus, and are expensive and environmentally harmful.

“An electrolyte allows lithium ions that carry an electric charge to move across a separator between the positive and negative terminals of a lithium-ion battery,” explains Apparao Rao, one of the researchers. “By modifying affordable commercial coolants to function as battery electrolytes, we were able to produce a battery that puts out its own fire.”

The result, according to the study, is a battery that works in a temperature range from -75°C to 80°C. Researchers say the results of the study are particularly promising for the electronics and electric vehicles market, which are dominated by lithium-ion batteries that use organic, flammable molecules.

“For a single electrolyte chemistry, improving its safety is often at the expense of cost and the battery’s electrochemical performance. Here we show an electrolyte that breaks this trade-off with combined flame retardancy, cost advantage and excellent cycling performance in both potassium-ion and lithium-ion batteries,” researchers say.