MIT Researchers Make Significant Advance in Lithium-Air Batteries

Lithium-air batteries are one of those technologies that could be truly revolutionary. With a theoretical maximum energy storage capacity 10 times greater than your garden variety lithium-ion battery, lithium-air batteries could be much smaller and lighter but still provide a huge range. How’s 500-700 miles per charge for you?

Unfortunately, as is usually the case with these sorts of things, the lithium-air revolution has hurdles aplenty. But fortunately, lithium-air batteries have some big guns doing research on them. For instance, IBM has been doing research on lithium-air batteries for the better part of a decade.

And just this week, scientists at MIT have announced that when they substituted gold and platinum for the standard carbon electrodes in lithium-air cells, they were able to obtain much higher efficiencies. The find was significant enough for MIT to claim that their research could lead to lithium-air batteries with 3 times the energy density of lithium-ion. That alone would be a big step forward.

Although the findings provide hope, they also highlight some major problems. For one, gold and platinum are extremely expensive. As one of the major goals in battery research is not only to increase storage capacity, but to bring battery cost down, you can see how that might be prohibitive. To get at this problem the research team, headed by professor Yang Shao-Horn, is already thinking of developing even better electrodes that are cheaper alloys of platinum or gold or even cheaper metal oxides.

One of the other main hurdles to lithium-air batteries is the fact that they could be extremely explosive. Lithium-ion batteries are already dangerous enough due to the flammable nature of metallic lithium. But because lithium-ion batteries are made of inorganic materials and are not exposed to air, the safety issue has been largely dealt with at this point.

But lithium-air batteries, by the nature of their being filled with, uh, air, are much more susceptible to the runaway reaction that can cause lithium-based batteries to explode. But professor Shao-Horn says that this issue can be dealt with in lithium-air batteries by using a form of lithium other than metallic lithium. Lithium-air batteries are also currently not very durable, only withstanding a limited number of charge and discharge cycles before degrading beyond usability.

Like I said, it’s not a sure thing by any means and potentially revolutionary research is not for those with lack of vision. As Shao-Horn says, “It’s a very promising area, but there are many science and engineering challenges to be overcome.” There’s an understatement for the ages.

Source & Image Credit: MIT

 

Nick Chambers

Not your traditional car guy.