A new lithium-oxygen battery is being touted as potentially able to provide much longer ranges between charges for EVs. Also known as lithium-air, the tech has been in the news before with promise for five to 15-times more efficiency than standard lithium-ion batteries. However, it has been held back by a few issues such as loss of about a third of its energy as heat, not lasting long enough, but research continues, including a new study which has shown encouraging results.
The study is led by Ju Li, professor of nuclear science and engineering at the Battelle Energy Alliance and Massachusetts Institute of Technology, along with fellow MIT researcher Zhi Zhu and five other researchers. All of the researchers work for either MIT, Argonne National Laboratory, or Peking University, and their labor shows a new version of the technology could overcome obstacles.
The team is looking to have a prototype produced within a year and available to manufacturers within the next 18 months. The researchers have renewed the practical patent application and are now seeking investors. The tech, they said, can work with smartphones, too – and the idea of not having to charge a smartphone every day could be just as appealing to investors as the idea of not having to charge an EV as often.
Other promises made about battery tech have fizzled, but the details here suggest that maybe the challenges of lithium-air batteries have been surmounted.
The new tech, which was detailed in Nature, uses what’s called a nanolithia cathode battery. This type of battery offers more versatility and avoids some of the issues that held back previous lithium-oxygen batteries – issues like needing to be kept away from carbon dioxide and water.
Existing lithium-oxygen batteries work by drawing air in, which causes a chemical reaction – air is then later released to reverse the reaction, which then recharges the battery.
Of course, having an airflow that works both ways allows carbon dioxide and water to enter. So the researchers figured out a way to recharge without letting oxygen become a gas.
“Instead, the oxygen stays inside the solid and transforms directly between its three redox states, while bound in the form of three different solid chemical compounds, Li2O, Li2O2, and LiO2, which are mixed together in the form of a glass,” the researchers wrote. “This reduces the voltage loss by a factor of five, from 1.2 volts to 0.24 volts, so only eight per cent of the electrical energy is turned to heat.”
This leads to lower waste via heat, which leads to better efficiency and faster recharging. Not only that, but the batteries could have longer lives than current lithium-ion batteries, since this particular reaction doesn’t lead to overcharging.
“We have overcharged the battery for 15 days, to a hundred times its capacity, but there was no damage at all,” Li said.