This Lithium-Sulfur Battery with New Electrolyte Significantly Boosts Operating Temperature Range

A team of scientists from the University of California at San Diego have shown off a new lithium-sulfur battery that, they say, can operate at temperature extremes impossible for current technologies — which could come as welcome news for everything from search-and-rescue drones to exploratory spacecraft.

Lithium-based batteries have become the go-to for powering everything from smartwatches to drones and electric cars, but while they offer excellent energy densities they come with disadvantages too — not least of which is a narrow operating temperature range. It's this the San Diego team has sought to resolve, designing a new battery based on a sulfur cathode and novel electrolyte capable of operating where traditional lithium-ion batteries fear to tread.

"All-climate temperature operation capability and increased energy density have been recognized as two crucial targets, but they are rarely achieved together in rechargeable lithium (Li) batteries," the team explains in the abstract to its paper. "Herein, we demonstrate an electrolyte system by using monodentate dibutyl ether with both low melting and high boiling points as the sole solvent."

The result of this new electrolyte and sulfur cathode: a battery that can reliably discharge and be recharged at temperatures below -30°C and above 45°C (-22°F and 113°F respectively). Unlike earlier lithium-sulfur battery designs, which have been dogged by short lifespans, the team's prototype tested through 200 charge-discharge cycles and retained over 87 percent of its design capacity at -40°C (-40°F). When heated to 50°C (122°F), meanwhile, the battery actually gained 15 percent capfacity — something the team will have to keep an eye on to ensure safety and longevity.

Thus far, the researchers have not disclosed a timeline for potential commercialization — but believe they can tweak the design to boost energy storage capacity as well the operating temperature range, potentially as high as 50 percent above existing lithium-ion cells.

The team's paper has been published in the journal Proceedings of the National Academy of Science (PNAS) under closed-access terms, with more information available on IEEE Spectrum.