The new design of the lithium-air battery could offer a much longer driving range compared to the lithium-ion battery

Many electric car owners have desired a battery pack that can drive their vehicle more than a thousand miles on a single charge. Researchers at the Illinois Institute of Technology (IIT) and the US Department of Energy’s (DOE) Argonne National Laboratory have developed a lithium-air battery that could make that dream a reality. The team’s new battery design could also one day power domestic planes and long-haul trucks.

The key new component in this lithium-air battery is a solid electrolyte instead of the usual liquid variant. Solid electrolyte batteries do not suffer from the safety issue with the liquid electrolytes used in lithium-ion and other types of batteries, which can overheat and catch fire.

More importantly, the team’s solid electrolyte battery chemistry can potentially increase energy density fourfold over lithium-ion batteries, which translates into longer range.

“For over a decade, scientists in Argonne and elsewhere have been working overtime to develop a lithium battery that uses the oxygen in the air,” said Larry Curtiss, an Argonne Distinguished Fellow. “The lithium-air battery has the highest projected energy density of any battery technology being considered for the next generation of batteries beyond lithium-ion.”

In previous lithium-air designs, the lithium in a lithium metal anode moves through a liquid electrolyte to combine with oxygen during discharge and form lithium peroxide (Li₂O₂) or superoxide (LiO₂) at the cathode. The lithium peroxide or superoxide is then broken down back into its lithium and oxygen components during the charging process. This chemical sequence stores and releases energy as needed.

The team’s new solid electrolyte consists of a ceramic polymer material made from relatively inexpensive elements in nanoparticle form. This new solid enables chemical reactions involving lithium oxide (Li₂O) upon dismissal.

“The chemical reaction for lithium superoxide or peroxide involves only one or two stored electrons per oxygen molecule, while that for lithium oxide involves four electrons,” said Argonne chemist Rachid Amine. More stored electrons mean higher energy density.

The team’s lithium-air design is the first lithium-air battery to achieve a four-electron reaction at room temperature. It also works with oxygen supplied by ambient air. The ability to run on air avoids running oxygen tanks, a problem with previous designs.

The team used many different techniques to determine that a four-electron reaction was indeed taking place. A key technique was transmission electron microscopy (TEM) of the discharge products on the cathode surface, performed at the Argonne Center for Nanoscale Materials, a user facility of the DOE Office of Science. The TEM images provided valuable insights into the four-electron discharge mechanism.

Previous lithium-air test cells suffered from very short cycle lives. The team found that this deficiency is not the case with their new battery design by building and operating a test cell for 1000 cycles and demonstrating its stability under repeated charging and discharging.

“We expect that as our new lithium-air battery design continues to be developed, it will also achieve a record energy density of 1200 watt-hours per kilogram,” said Curtiss. “That’s almost four times better than lithium-ion batteries.”

This research was published in a recent issue of Science. Argonne authors include Larry Curtiss, Rachid Amine, Lei Yu, Jianguo Wen, Tongchao Liu, Hsien-Hau Wang, Paul C. Redfern, Christopher Johnson, and Khalil Amine. The authors of the IIT include Mohammad Asadi, Mohammadreza Esmaeilirad and Ahmad Mosen Harzandi. University of Illinois Chicago authors include Reza Shahbazian-Yassar, Mahmoud Tamadoni Saray, Nannan Shan and Anh Ngo.