Blood molecule to help engineers build better batteries

NEW HAVEN, Conn., Oct. 20 (UPI) — Lithium-oxygen batteries hold much promise, but before they can supplant lithium-ion batteries as the industry standard they must overcome a number of problems.

To that end, researchers at Yale University have their sights set on an oxygen-carrying blood molecule they hope will make Li-O2 batteries commercially viable.

Lithium-oxygen batteries can old a charge for an impressive period of time, but they’re inefficient. They also produce lithium peroxide, which builds up on the oxygen electrodes and inhibits performance.

Researchers have been looking for a catalyst that can trigger the decomposition of lithium peroxide and other lithium oxide byproducts back into lithium ions and oxygen. Now, scientists at Yale believe they’ve found what they’ve been looking for.

Heme is a type of molecule found in hemoglobin, the red pigment in blood. In lab tests, scientists proved that its introduction to Li-O2 batteries could reduce the energy required to boost the efficiency of the batteries’ charge-discharge cycles.

As researchers explained in a new paper on the research — published this week in the journal Nature Communications — the heme molecules work as a redox mediator, lowering the energy threshold required to trigger electrochemical reactions.

“When you breathe in air, the heme molecule absorbs oxygen from the air to your lungs and when you exhale, it transports carbon dioxide back out,” Andre Taylor, associate professor of chemical and environmental engineering, said in a news release. “So it has a good binding with oxygen, and we saw this as a way to enhance these promising lithium-air batteries.”

If the discovery can be commercially realized, it would be a boon to the animal products industry, which currently has to find ways to safely dispose of blood.

“We’re using a biomolecule that traditionally is just wasted,” said Taylor. “We can take the heme molecules from these waste products and use it for renewable energy storage.”