Chinese lithium-ion capacitor operates reliably at -100°C

New energy storage systems for the Arctic and space could be developed from this technology

Chinese researchers have produced a lithium-ion capacitor that can operate reliably at -100°C. The achievement sets a new record for devices in this class.

Why conventional lithium-ion systems struggle in extreme cold

The study was carried out by a team led by Ma Yanwei of the Institute of Electrical Engineering at the Chinese Academy of Sciences, working with colleagues from the Changchun Institute of Applied Chemistry and Tsinghua University's Shenzhen International Graduate School. The scientists explain that below -20°C, standard lithium-ion systems rapidly become less effective as electrolyte viscosity rises, ionic conductivity falls and resistance at phase boundaries increases sharply.

A low-temperature electrolyte for lithium-ion capacitors

To overcome this limitation, the researchers designed a new electrolyte for low-temperature use. Its solvent molecular structure was modified by introducing fluorine-containing groups. This chemical design retained high ionic conductivity, low viscosity and stable interfacial behaviour even under exceptionally low temperatures.

Using the new electrolyte, the team built a 1100 F lithium-ion capacitor that successfully delivered a stable discharge at -100°C. According to the authors, the research not only removes one of the major barriers to energy storage in extreme cold, but also provides a theoretical basis for developing new electrochemical systems for particularly harsh operating environments.