Science: Jumpstarting the Lithium-Air Battery

A new study published in Science brings scientists one step closer to developing a lithium-air battery, which could someday be lighter and last longer than the lithium-ion batteries currently found in cell phones, laptops, and hybrid cars.

Lithium-air batteries are a hot area of investigation—a handful of research institutions and companies are currently exploring the technology for use in vehicles. However, the technology is in its infancy and many challenges to a practical rechargeable lithium-air battery remain.

“The work demonstrates the essential role of fundamental science in making progress in what are relatively new frontiers in energy storage,” said Peter Bruce, professor at the University of St. Andrews in the UK and senior author of the study.

All batteries consist of a negative and positive electrode separated by an electrolyte. Lithium-air batteries are appealing because they can use oxygen, a lightweight, abundant molecule, to induce current flow. Oxygen from the air enters through a porous cathode and combines with electrons and lithium ions to form the solid product, lithium peroxide.

However, an ongoing problem with these batteries is that side reactions with the electrolyte can cause degradation and poor performance as the battery experiences repeated charging and discharging cycles.

Bruce and colleagues discovered that using an ionic liquid for the electrolyte solves the stability problem, and that using a nanoporous gold electrode gives the battery faster operating characteristics when compared with traditional porous carbon electrodes.

“While nanoporous gold is not a practical electrode, we were excited to discover that a lithium-oxygen battery capable of sustained cycling by repeated and reversible lithium peroxide formation/decomposition at the cathode is possible,” said Bruce.

“Demonstrating repeated and reversible lithium peroxide formation/decomposition is important if a lithium-air battery with a non-aqueous electrolyte is ever to succeed.”

The new research is published in the 19 July issue of Science.

Links

Read the abstract, “A Reversible and Higher-Rate Li-O2 Battery,” by Peter Bruce and colleagues.