Chinese Scientists Create Cold-Resistant Electrolyte for Lithium Batteries

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A research team in China has innovated a new electrolyte that markedly enhances lithium battery performance in extremely cold temperatures, opening new possibilities for electric vehicles, space exploration, and robotics, according to a recent publication in Nature.

This advancement tackles a long-standing challenge with lithium batteries, which often struggle to perform below -50°C. The new electrolyte formulation enables batteries to store nearly 400 watt-hours per kilogram even at -50°C, a significant improvement over the typical 100 to 300 watt-hours per kilogram seen in commercial batteries today.

The study was carried out by scientists from Nankai University’s College of Chemistry and the Shanghai Institute of Space Power Sources. They engineered a fluorinated hydrocarbon solvent molecule and developed an electrolyte system that replaces the conventional lithium-oxygen coordination pattern usually found in standard electrolytes.

Electrolytes act as the vital medium for conducting charged ions between a battery’s positive and negative electrodes. Current mainstream electrolytes generally contain lithium salts dissolved in carbonate solvents, relying on lithium-oxygen interactions to facilitate ion movement. However, poor wettability limits the energy density, and low-temperature charge transfer capacity prevents effective operation below -50°C.

To address these issues, the research team proposed substituting oxygen atoms with fluorine atoms in the electrolyte to better dissolve lithium salts. This innovation resulted in a lithium battery capable of reaching an exceptional energy density of 700 watt-hours per kilogram at room temperature, while maintaining nearly 400 watt-hours per kilogram at -50°C.

For comparison, typical commercial lithium batteries range from 100 to 300 watt-hours per kilogram in energy density. The 4680 battery produced by Tesla, for instance, approaches 300 watt-hours per kilogram.

Batteries with high energy densities based on this new electrolyte could have wide-ranging applications in electric vehicles, intelligent robotics, low-altitude aerospace operations, and more, stated Chen Jun, associate president of the university and one of the lead researchers.