MIT Announces Exciting New Lightweight Battery Advancement – by Guest Blogger Kathy Heshelow

The press office at Massachusetts Institute of Technology (MIT) announced this week that a team of researchers has made a breakthrough on battery technology in the form of lightweight lithium-air batteries could have three times the energy density of current models.

Lithium-ion batteries currently dominate the field of small electronics — and are the prime candidates for electric vehicles. Lithium-ion batteries use a light metal (lithium), and they don’t suffer power loss when they are charged up time and time again. However, for such applications as in an electric vehicle, they are still heavy, and researchers have been working hard to improve energy density – the amount of energy stored by kilogram. Lithium-air batteries use the same general concepts, but replace the heavier compounds found in lithium-ion batteries, which makes them lighter. In fact, the research team says that their breakthrough could lead to batteries with three times the energy density of existing batteries.

Lead author of the paper published in Electrochemical and Solid-State Letters, doctoral student Yi-Chun Lu, says that the team developed a method for analyzing activities of different catalysts in the batteries — and that they can now build on this research with a variety of materials. The paper is entitled “The Influence of Catalysts on Discharge and Charge Voltages of Rechargeable Li-Oxygen Batteries” by Yi-Chun Lu, Hubert A. Gasteiger, Michael C. Parent, Vazrik Chiloyan and Yang Shao-Horn. Funding came from the Department of Energy, National Science Foundation and Martin Family Society of Fellows.

MIT associate professor of mechanical engineering Yang Shao-Horn reported that several groups have been working on lithium-air batteries. They want to achieve gains in energy density, power and weight. Lithium-air batteries, she says, have been less understood than lithium-ion batteries.

A researcher at GM Research & Development in Michigan, Gholam-Abbas Nazri, said that the research is important, and that it is “in the right direction for further understanding of the role of catalysts. He adds, “this may significantly contribute tothe future understanding and development of lithium-air systems.” (MIT Press. “MIT takes a step closer to lightweight batteries”. David Chandler. April 2, Office 2010.)

Why is This Important?

Lightweight batteries with more strength are crucial for many important applications in our new sustainable world — not the least electric vehicles. “Even modest increases in a battery’s energy-density rating …are important advances.” (MIT Press Office. “MIT takes a step closer to lightweight batteries”. David Chandler. April 2, 2010).

Lithium

Lithium (Li) is a soft-silver white metal in the alkali metal group. In its elemental state, it is highly flammable. Like all alkali metals, it is quite reactive and corrodes quickly in the presence of water or moist air. Hence, it is often stored under the cover of petroleum. According to Environmental Chemistry.com, lithium was first isolated in 1821 by W. T. Brande. Lithium is widely distributed on Earth but does not naturally occur in elemental form.

There are various applications for lithium today, such as use in the fire-chemical industry, use in nuclear reactor coolants, medical applications (such as for bipolar disorders), in certain lubricants, propellants and additives, and in some focal lenses (telescopes, spectacles), to name a few examples. Lithium is most commonly known to be used in batteries.

What’s Next?

Researchers have identified several issues that need to be addressed in order to facilitate their work in bringing lithium-air to a practical use. In particular, Shao-Horn says that the same battery principle as lithium-ion could be applied without lithium, perhaps using graphite or some other more stable negative electrode material, which would lead to a safer system. Lithium is very reactive in the presence of water and it is also toxic in solution.

Work is also being done to help lithium-air batteries improve performance through a number of charges for practical commercial products. “We are at the very beginning” of understanding how the reactions of various compounds react with other compounds and details of their chemistry in the charging process, said Shao-Horn. IBM and General Motors, among others, have committed themselves to ongoing research in initiatives on lithium-air, also known as lithium-oxygen. Lighter yet stronger batteries are needed to develop the electric vehicle industry.