Researchers at Rensselaer Polytechnic Institute (RPI) have developed a new type of material made from “nanoscoops”, which can increase the charging speed of small lithium-ion batteries by 40-60 times. Previously the anodes in lithium ion batteries — lithium ion molecules which travel between anodes and cathodes to create a charge — would become stressed, swell, and wear out if charged quickly, so batteries were designed to charge at a snail’s pace. Nanoscoops are specifically designed to withstand the stress of a quick charge and won’t swell under the pressure. If scaled up, this technology could mean less waiting around to charge for the owners of electric vehicles.
When left to charge in a regular household outlet (110/120 volt, 15-amps), a Nissan Leaf could take up to 20 hours to charge. A level 2 charging station brings that pace to a bearable 8 hours, but scientists around the world are working to make that time even shorter.
The researchers at RPI seem to have been successful with the development of nanoscoops. “If you charge and discharge [conventional lithium ion batteries] very slowly then the stress buildup is not that serious a problem, but if you try to charge and discharge too quicky then the stress buildup is so instantaneous that it becomes a problem … slowly the battery starts to get worse and worse, and then at some point it will fail completely,” said Nikhil Koratkar, co-author of the study and a professor at RPI. Though they’ve only tested their technology in a battery the size of a coin, they believe it will be scalable.
RPI’s new nanoscoop anodes are made from layers and layers of nanomaterials — thin coats of aluminum topped with a layer of silicon. Each layer acts as a sponge for the stress of the next layer, and together they reduce stress upon the anode when charging. “The advantage of nanoscale is that the structures are very flexible,” Koratkar said. “They can withstand a change in volume, and they tend not to fracture and fail.” As for now the nanoscoops are tiny — they measure about 170 nanometers — and they need to be made longer and larger in order to be used in larger batteries.
Via Tech News Daily