Chinese scientists have overcome a long-standing limitation of lithium batteries by developing a new component that may lead to doubling of electric vehicle ranges.
Lithium batteries, widely used in EVs, typically rely on interactions between lithium salts and oxygen atoms in a solvent to produce power. A chemical reaction dissolves the salts to enable lithium ions to travel through the electrolyte, a process that generates an electrical current.
But these batteries require solvents in large quantities, leading to difficulties in reducing their size.
The solvents also don’t work well under low temperatures, making them less effective in the colder parts of the world.
The batteries moreover function near their theoretical limit of 350 watt-hours per kg, forcing many companies to shift to solid-state batteries.
But the newly developed battery can achieve energy densities “greater than 700wh per kg at room temperature and nearly 400wh per kg at -50C”, the researchers say in a new study published in the journal Nature.
The new battery uses a “fluorinated hydrocarbon” solvent that enables effective dissolution of lithium salts. The solvent replaces the traditional lithium-oxygen model and offers much better efficiency, significantly reducing the amount of electrolyte, according to the Chinese scientists.
“An electrolyte needs to release ions fast and also enable quick charge transfer, but those two things usually conflict,” Nankai University professor Zhao Qing explained.
“Fluorine’s weaker pull on lithium helps resolve that.”
The lithium-fluoride system enables rapid charge transfer processes even at low temperatures, researchers say, adding that it can work even in environments as cold as -50C.
“This breakthrough could double the capacity of existing lithium batteries without increasing their size or weight,” the researchers said, according to state broadcaster CCTV.
“Electric vehicles with a current range of 500km could travel more than 1,000km on a single charge using our batteries,” said Chen Jun, lead author of the study from Nankai University.
The innovation brings the energy density of typical lithium batteries to the level of solid-state cells.
As the new battery performs efficiently even at very low temperatures, the researchers hope they can find use in vehicles and drones meant for high altitudes.
