Lithium-air batteries can power future electric cars: Scientists

Tokyo: Scientists are working on a new type of battery to power gen-next electric cars that could be up to three times more efficient than existing ones.

Regular lithium-ion power-storage devices allow a maximum range of around 160 kilometres. "Lithium-air batteries are lightweight and deliver a large amount of electric energy. Many people expect them to one day be used in electric vehicles," said Nobuyuki Imanishi, Researcher. The main difference between lithium-ion and lithium-air batteries is that the latter replaces the traditional cathode - a key battery component involved in the flow of electric current, with air. That makes the rechargeable metal-air battery lighter with the potential to pack in more energy than its commercial counterpart.

One of the main components researchers are working on is the ‘electrolytes’ that conduct electricity between the electrodes. There are currently four electrolyte designs, one of which involves water. The advantage of this is to protect the lithium from interacting with gases in the atmosphere and enables fast reactions at the air electrode. Imanishi's team developed a layered approach, sandwiching a polymer electrolyte with high conductivity and a solid electrolyte in between the lithium electrode and the watery solution. The result was a unit with the potential to pack almost twice the energy storage capacity, as measured in Watt hours per kilograms (Wh/kg), as a lithium-ion battery.

"Our system's practical energy density is more than 300 Wh/kg. That's in contrast to the energy density of a commercial lithium-ion battery, which is far lower, only around 150 Wh/kg," concluded Imanishi.