The automotive industry is eager to see an electric vehicle (EV) battery that can be fully charged within five minutes, about the time it takes to fill a conventional vehicle’s gas tank. Actual charging time for an EV is over four hours.
Scientists at the Nanyang Technological University (NTU) in Singapore have developed such a battery. In tests at the university labs, the researchers demonstrated that the new battery could be charged up to 70% of its total charge in just two minutes, while enduring 20 times more charging cycles than today’s batteries. The team of researchers, led by Professor Chen Xiaodong from the School of Material Science and Engineering at NTU, developed this battery by replacing the traditional lithium-graphite anode in lithium-ion batteries with a new gel material made from titanium dioxide. This compound is very abundant, cheap and safe for human handling. It is commonly used as a food additive or in sunscreens to absorb UV rays.
To enhance the speed of the charging process, Professor Chen developed a method to convert the titanium dioxide particles into nanotubes. These nanotubes help to speed up the charging process by triggering a chemical reaction in the anode of the battery. "Manufacturing this new nanotube gel is very easy. Titanium dioxide and sodium hydroxide are mixed together and stirred under a certain temperature. Battery manufacturers will find it easy to integrate our new gel into their current production processes," Professor Chen said.
Professor Rachid Yazami, the scientist who 34 years ago invented the graphite anode used in lithium-ion batteries today, said that Chen's invention is the next big leap the scientific community was waiting for. “While the cost of lithium-ion batteries has been significantly reduced and their performance improved since Sony commercialized it in 1991, the market is expanding towards new applications in electric mobility and energy storage," said Professor Yazami. "There is still room for improvement and one such key area is the power density - how much power can be stored in a certain amount of space - which directly relates to the fast charge ability. Ideally, the charge time for batteries in electric vehicles should be less than 15 minutes, which Prof Chen's nanostructured anode has proven to do," he adds.
A paper published in the journal Advanced Materials describe the invention. The technology invented by Chen is being licensed to a company. It is expected that in two years’ time a new generation of fast-charging lithium-ion batteries will be available. "With our nanotechnology, electric cars would be able to increase their range dramatically with just five minutes of charging, which is on par with the time needed to pump petrol for current cars," added Prof Chen. "Equally important, we can now drastically cut down the waste generated by disposed batteries, since our batteries last ten times longer than the current generation of lithium-ion batteries," he adds.
