engineers at the university of california san diego have developed electrolytes from liquified gas that enable lithium-ion batteries to function at temperatures as low as -60°c and electrochemical capacitors to run as low as -80°c, while not losing performance at room temperature, according to a report on the school’s website.

uc san diego researchers were able to operate a battery at -60°c.
(uc san diego/youtube)

the article explained, “the technology could allow electric vehicles in cold climates to travel farther on a single charge, alleviating range anxiety during the winter in places like boston. the technology could also be used to power craft in the extreme cold, such as high atmosphere wifi drones and weather balloons, satellites, interplanetary rovers and other aerospace applications.”

the engineers turned to liquified gas because it is more resistant to freezing than standard liquid electrolytes. for the battery, the engineers chose to use liquified fluoromethane gas and, for the capacitor, they selected liquified difluoromethane gas.

researchers believe that the bottleneck for developments in energy storage system has been the electrolyte and while many have turned to solid state as the next generation technology, uc san diego engineers are the first to explore the potential of gas-based electrolytes.

the article added, “in pursuing this project, the uc san diego team realized that gases have a property that would make them work particularly well at temperatures where conventional liquid electrolytes would freeze — low viscosity.”

in addition, “with these new electrolytes, the battery will be unable to self-heat at temperatures much higher than room temperature. that’s because at high temperatures, these electrolytes lose the ability to dissolve salts, so the battery loses conductivity and stops working.”

the new liquified gas electrolytes also worked well with lithium metal, which is considered the ideal electrode material. the uniform interphase on the electrode prevents dendrites from forming that could short-circuit the battery and allows for greater efficiency in charge and discharge cycles for better performance.

the work was recently published in science. the abstract stated:

“electrochemical capacitors and li-ion batteries have seen little change in their electrolyte chemistry since their commercialization which has limited improvements in device performance. combining superior physical and chemical properties and a high dielectric-fluidity factor, the use of electrolytes based on solvent systems which exclusively use components which are typically gaseous under standard conditions show a wide potential window of stability and excellent performance over an extended temperature range.

“electrochemical capacitors using difluoromethane show outstanding performance from -78 to +65°c with an increased operation voltage.

“the use of fluoromethane shows a high coulombic efficiency of ca. 97% for cycling lithium metal anodes, together with good cyclability of a 4 v lithium cobalt oxide cathode and operation as low as -60°c with excellent capacity retention.”

see the battery in action at low temperatures in the video below: