Google "lithium-ion battery explosion" and you'll find enough YouTube videos and even more still shots of charred electronics to feel a tinge of fear about the batteries lurking inside your laptop.

Maybe that's just me. But lithium-ion batteries—which make our lightweight, high-powered electronics possible—do carry a small but real flammability risk from one of their key chemical ingredients. A team of scientists has now tested an alternative battery ingredient that would make battery fires a thing of the past.

For small and well-maintained batteries, the risks of a battery explosion are relatively low, but potential applications for large-scale batteries to provide backup power to airplanes or electrical grid scale storage are seriously limited by the inherent flammability.

The (rare) explosions are the result of a process known as thermal runaway—a positive feedback loop where increased temperatures accelerate the breakdown reaction of the battery's electrolyte, which produces more heat, which then speeds up the reaction even more.

The electrolyte facilitates the movement of the lithium ions from the anode to the cathode and in commercial batteries and is made with organic solvents. A common solvent, dimethyl carbonate, DMC, has a high risk of ignition. Finding a non-flammable replacement for the solvent would open up the battery technology to safer use and new applications, and many researchers are on the hunt.

A team of scientists based at the University of North Carolina at Chapel Hill recently shared their findings on a promising replacement—a fluoride polymer known as perfluoropolyether, PFPE. The polymer is similar to another well-studied poly-ether potential electrolyte, which was found to have relatively low conductivity.

Unlike the conventional DMC, which is flammable at ambient temperatures, the PFPE shows no risk of ignition below 200°C. To test the PFPE in typical battery systems, the researchers modified the chemical to attach methyl carbonate groups to the ends of the long, stable polymer chain, creating PFPE-DMC.

They then built standard coin-cell batteries using the PFPE-DMC as the electrolyte between a high-voltage cathode of lithium nickel–manganese–cobalt oxide and a lithium metal anode. In cycling tests, the experimental battery had a capacity of 120 compared to 150 for conventional batteries for a 10-hour charge. The charge and discharge rates were stable, suggesting good compatibility with the electrodes.

In tests for conductivity, the researchers found that their experimental electrolyte had a slightly lower ability to carry the current than conventional batteries, but they also found that the PFPE-DMC had really high transference numbers. The transference number basically indicates what fraction of the current is carried by the anion or cation; in this case the cation carries most of the current, which benefits battery performance. In their paper, the scientists write that this "unprecedented" transference could make up for the chemicals' shortcomings in the conductivity.

Like any new technology, further experiments are needed to refine the PFPE's conductivity and performance, but because the PFPE can be easily integrated into the standard battery design and other components, PFPF-batteries could be manufactured without investments in new infrastructure. Inherently nonflammable batteries could open doors to new applications that have been on hold because of the safety risks of the existing options.

PNAS, February 2014. DOI: 10.1073/pnas.1314615111