Nanotech Lithium-Oxygen Battery Overcomes Design Issues

This image shows nanometer-scale particles made of lithium and oxygen compounds (depicted in red and white) which are embedded in a sponge-like lattice (yellow) of cobalt oxide, which keeps them stable, overcoming some existing issues in lithium-air battery designs. (Image courtesy of MIT.)

With complex phone apps draining batteries faster than ever, improving the lifespan of our batteries is of paramount importance to many people.

In a bid to fill this need, researchers at MIT have developed a variation of battery chemistry by looking at lithium-air batteries as a starting point.

The new battery concept is called a nanolithia cathode battery and it works by containing the lithium and oxygen nanoparticles (nanolithia) within a cobalt oxide lattice, maintaining the solid state of the oxygen and removing the need for handling the gaseous O₂.

The nanoparticles are maintained as a glass and within, the transitions between LiO₂, Li₂O₂, and Li₂O can take place entirely inside the solid material. The cobalt oxide matrix maintains the stability of the nanolithia and acts as a catalyst for the chemical transitions.

Conventional lithium-air batteries, as explained by Ju Li, the Battelle Energy Alliance professor of nuclear science and engineering at MIT, are “really lithium-dry oxygen batteries, because they really can’t handle moisture or carbon dioxide. You need large auxiliary systems to remove the carbon dioxide and water and it’s very hard to do this.”

This new battery doesn’t require any outside air to supply its oxygen, resulting in smaller, simpler, and cheaper batteries.

The team also noted that the new battery is inherently protected from overcharging—a danger in existing batteries that can lead to degradation of the battery or worse.

“With a typical battery, if you overcharge it, it can cause irreversible structural damage or even explode,” Li said.

“We have overcharged the battery for 15 days to a hundred times its capacity, but there was no damage at all,” Li added.

Lithium-air batteries are promising because of their potential to deliver a high output of energy and retain their performance after repeated charging cycles. This makes them strong candidates for mobile devices and electric cars. The mechanical drawback of requiring a system to handle feeding air to the battery has been a stumbling block, among other issues.

This new development could lead to a breakthrough in battery chemistry and design. Li and his team hope to have a practical prototype in about a year.

Read more on Ju Li and his work at MIT’s Department of Materials Science and Engineering website, or the paper, “Anion-redox nanolithia cathodes for Li-ion batteries,” published in the journal Nature Energy.

For more on advancements in battery technology, check out this new concept for a gravity-fed flow battery.