Many groups are pursuing work on lithium-air batteries, a technology that could deliver a significant increase in energy density over lithium-ion batteries. (Earlier post.) However, notes Shao-Horn, there has been a lack of understanding of what kinds of electrode materials could promote the electrochemical reactions that take place in these batteries.

The MIT team developed a method for analyzing the activity of different catalysts in the batteries, and now can build on this research to study a variety of possible materials.

We’ll look at different materials, and look at the trends. Such research could allow us to identify the physical parameters that govern the catalyst activity. Ultimately, we will be able to predict the catalyst behaviors.

—Yi-Chun Lu, lead author

A number of issues must be addressed before lithium-air batteries can become a practical commercial product, Shao-Horn says. The biggest issue is developing a system with sufficient cycle life for it to be useful in vehicles or electronic devices.

Researchers also need to look into details of the chemistry of the charging and discharging processes, to see what compounds are produced and where, and how they react with other compounds in the system. “We’re at the very beginning” of understanding exactly how these reactions occur, Shao-Horn says.

Gholam-Abbas Nazri, a researcher at the GM Research & Development Center in Michigan, called this research “interesting and important,” and says this addresses a significant bottleneck in the development of this technology: the need find an efficient catalyst.

While some companies working on lithium-air batteries have said they see it as a 10-year development program, Shao-Horn says it is too early to predict how long it may take to reach commercialization. “It’s a very promising area, but there are many science and engineering challenges to be overcome,” she says. “If it truly demonstrates two to three times the energy density” of today’s lithium-ion batteries, she says, the likely first applications will be in portable electronics such as computers and cell phones, which are high-value items, and only later would be applied to vehicles once the costs are reduced.

Resources

• Yi-Chun Lu, Hubert A. Gasteiger, Michael C. Parent, Vazrik Chiloyan, Yang Shao-Horn (2010) The Influence of Catalysts on Discharge and Charge Voltages of Rechargeable Li-Oxygen Batteries. Electrochemical and Solid-State Letters, Vol. 13, No. 6 doi: 10.1149/1.3363047

• Electrochemical Energy Lab at MIT