Scientists Develop New Low Cost, Rechargeable Zinc-Air Battery

Scientists from Stanford University have developed a new zinc-air battery, which promises high stability and catalytic activity at low-cost.

Scientists may have a solution to the highly expensive conventional lithium-ion batteries, which are widely used for various electrical purposes. Despite the limited energy density, high cost and safety risks, people have no choice but to opt for the lithium-ion batteries. Not anymore, as the Stanford University scientists have developed an advanced zinc-air battery, which delivers a better performance than the lithium-ion batteries but do not use expensive metals like platinum and iridium catalysts.

The metal-air batteries have greater theoretical energy density than the aqueous batteries or lithium-ion batteries because of the abundance of oxygen in the atmosphere, according to Hongjie Dai, professor of chemistry at Stanford and lead author of the study. He said that the use of low-cost zinc metal makes the metal-air batteries non-flammable and safe to use.

Developing rechargeable metal-air batteries was a great challenge for Dai and his team. "Primary (non-rechargeable) zinc-air batteries have been commercialized for medical and telecommunication applications with limited power density," he said in a press release. "However, it remains a grand challenge to develop electrically rechargeable batteries, with the stumbling blocks being the lack of efficient and robust air catalysts, as well as the limited cycle life of the zinc electrodes."

Dai and his team used a different technology to boost performance in the zinc-air batteries. Active and long-lasting electrocatalysts in the air electrodes play an important role in charging and discharging batteries by catalyzing oxygen-reduction and oxygen-evolution, respectively. Both catalytic reactions were found to be slow in metal-air batteries, Dai said.

Dai and his team had previously developed 'Unzipped' carbon nanotubes with low-cost and abundant high-performing electrocatalysts. These catalysts produced higher activity and stability than the catalysts made with platinum and other precious metals.

"We found that similar catalysts greatly boosted the performance of zinc-air batteries [rechargeable and non-rechargeable]," Dai said. "A combination of a cobalt-oxide hybrid air catalyst for oxygen reduction and a nickel-iron hydroxide hybrid air catalyst for oxygen evolution resulted in a record high-energy efficiency for a zinc-air battery, with a high specific energy density more than twice that of lithium-ion technology."

Dai said that this could be an effective solution to the expensive aqueous batteries or lithium-ion batteries and has greater scope in the future.

The findings of the study are published in the journal Nature Communications, May 7.