MIT makes significant step toward lightweight batteries

A team of researchers at MIT has made significant progress on a technology that could lead to batteries with up to three times the energy density of any battery that currently exists.

Yang Shao-Horn, an MIT associate professor of mechanical engineering and materials science and engineering, says that many groups have been pursuing work on lithium-air batteries, a technology that has great potential for achieving great gains in energy density. But there has been a lack of understanding of what kinds of electrode materials could promote the electrochemical reactions that take place in these batteries.

Lithium-oxygen (also known as lithium-air) batteries are similar in principle to the lithium-ion batteries that now dominate the field of portable electronics and are a leading contender for electric vehicles. But because lithium-air batteries replace the heavy conventional compounds in such batteries with a carbon-based air electrode and flow of air, the batteries themselves can be much lighter. That’s why leading companies, including IBM and General Motors, have committed to major research initiatives on lithium-air technology.

In a paper published this week in the journal Electrochemical and Solid-State Letters, Shao-Horn, along with some of her students and visiting professor Hubert Gasteiger, reported on a study showing that electrodes with gold or platinum as a catalyst show a much higher level of activity and thus a higher efficiency than simple carbon electrodes in these batteries. In addition, this new work sets the stage for further research that could lead to even better electrode materials, perhaps alloys of gold and platinum or other metals, or metallic oxides, and to less expensive alternatives.

... Why it matters: Lightweight batteries that can deliver lots of energy are crucial for a variety of applications — for example, improving the range of electric cars. For that reason, even modest increases in a battery’s energy-density rating — a measure of the amount of energy that can be delivered for a given weight — are important advances.

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