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PRI's Environmental News Magazine

Molten Metals to Green the Grid

Air Date: Week of October 30, 2009

stream/download this segment as an MP3 file

“So much has to be invented,” Sadoway tells Living on Earth’s Jeff Young. “No one’s ever tried this kind of chemistry before.” It’s the kind of pioneering research the Dept. of Energy hopes might pay off with “transformational” technology.

The U.S. government is investing hundreds of millions in high risk, high reward research that could produce what it calls “transformational technology” that changes our energy future. Host Jeff Young visits the lab of a MIT scientist who got support to develop batteries made from molten metals. If it works, it could allow for massive storage of renewable energy for times when there’s not enough sun or wind.


YOUNG: Well, the Obama administration also wants the power that smart grid carries to come from cleaner sources. The Department of Energy just announced the first recipients of 400 million dollars in grants designed to push the boundaries of energy research. The winners are a mix of small technology companies and some of the country’s biggest research universities, like Penn State, Stanford and MIT. I visited MIT in Cambridge, Massachusetts, where President Obama issued this challenge to engineers and scientists.

OBAMA: From China to India, from Japan to Germany, nations everywhere are racing to develop new ways to produce and use energy. The nation that wins this competition will be the nation that leads the global economy. I am convinced of that. And I want America to be that nation. It’s that simple. (Applause.)

YOUNG: But just after this speech, I caught up with MIT president, Susan Hockfield, and asked what she thinks it will take to meet President Obama’s goal.

HOCKFIELD: The problem we face in this country is that it’s been a rollercoaster of support, it goes up when oil prices go up, it goes down when gas prices drop, and with that kind of rollercoaster, the problem is that you always end up at the starting gate. And so, in order to really create and energy revolution, we need sustained – a sustained commitment to energy R and D funding.

Susan Hockfield is President of MIT

YOUNG: Hockfield’s encouraged by the administration’s new approach to energy research. It’s modeled on the Defense Department’s Advanced Research Projects Agency – DARPA, as it’s known, made long-shot bets in high-risk research, and it gave us things like body armor and the Internet. Three years ago, a National Academy of Science’s paper called for the same kind of program for energy research, an ARPA-E. That paper was written by a Nobel-winning physicist named Stephen Chu.

CHU: If you look at what the United States has, it has unarguably the greatest research and development centers in the world, in our universities, our national labs, and in the private sector. And so, once we get this great innovation machine geared and going, we would be invincible. But, the only trouble is, let’s get it going.

YOUNG: Now, of course, he’s Energy Secretary Stephen Chu, and thanks to money from the Economic Stimulus Act, he’s awarding the first ARPA-E grants. 3,600 scientists applied for the first round, just 37 were approved. The winners included ideas for improving biofuels, others aim to capture carbon dioxide emissions, and some of the winners are looking for breakthroughs in batteries. And that brings us back to MIT:


Prof. Sadoway shows a cut-away of one of the small liquid metal batteries after it’s been tested. He can make them work at this size. Now he wants to try to make them big. Really big.

YOUNG: Down in the well-worn basement labs of MIT’s building number eight, Don Sadoway shows me his winning idea for a liquid metal battery. The materials chemistry professor’s been at MIT three decades. Now, the seven million dollar grant will help him scale up his latest project. He slips his hands into the black sleeves of an airless glove box, where some of the batteries – now solid at room temperature – have been cut in half.

SADOWAY: So, here’s – here’s one of them, you can see the upper layer here, there’s liquid metal that’s at the top…

YOUNG: Uh huh.

SADOWAY: This granular stuff is the electrolyte, which is a molten salt, and you can see a second shiny zone at the bottom here, which is the second liquid layer, and it’s self-assembled, self-separated; there’s no divider, no separator here.

YOUNG: So when this heats up, these metals kind of sort themselves out because they’re different densities, is that the deal?

SADOWAY: Exactly, you have two factors here: All three liquids are of different density, okay, and the second thing that’s equally important, they’re remissible just like oil and water because I don’t want to put any separators in here. That’s the virtue of it because it has no separator it’s – wherever you have a solid in a battery, solid means slow diffusion.

“So much has to be invented,” Sadoway tells Living on Earth’s Jeff Young. “No one’s ever tried this kind of chemistry before.”
It’s the kind of pioneering research the Dept. of Energy hopes might pay off with “transformational” technology.

YOUNG: Professor Sadoway wanted fast diffusion, and he got it with molten metals that very quickly charge and discharge. He’s cagey about the exact ingredients – he calls it the special sauce – but he says they’re readily available in the US. His demo batteries are the size of the Fresca soda cans he sips during lectures. One day, he hopes they could be big enough to be batteries for the electric grid, providing the storage for clean power like solar and wind need.

SADOWAY: And so storage is critical, but the storage has to be scalable, it has to be big, not a whole bunch of cell phone batteries strung together like Christmas tree lights.

YOUNG: So this little thing we’re looking at here fits in your hand; you could make that as big as…

SADOWAY: As big as this laboratory. You could have a single cell that is the size of this laboratory so we could be up to our knees in the metal that I won’t name on the bottom, and then maybe up to our waist in the molten salt, and them maybe a little higher up in the magnesium alloy, and it would have enormous capacity. And it’d be cheap to build.

YOUNG: So, they’re going to be storing the renewable energy that we produce, and then you’re going to even out that problem with the intermittency of solar or wind – that’s the vision for you.

SADOWAY: You got it. That’s it exactly.

YOUNG: It’s still more concept than product, and it might not work at the size needed. That’s the whole idea of the ARPA-E granting program. This is swing-for-the-fences science; many projects will miss, but if just a few hit, they become what Secretary Chu calls transformational technology. And professor Sadoway doesn’t need to look far for inspiration.

SADOWAY: Well, when we walk down the hallway to get to my lab, we walk underneath what was the radiation laboratory during World War Two, so radar was first developed there. If you go back to the 1950s, there was a fellow over in electrical engineering by the name of Forrester and he came up with the memory of the first main frame computers. Those are inventions that have enormous impact.

YOUNG: And you think a transformational piece might roll out of here?

SADOWAY: I’m going to give it my best shot. We’ve got good people. It’s a career with meaning. I think that’s what inspires people most, they want to work on this; they want to make a difference. And if you’ve got good people and you’re properly resourced, you’ve got a really good chance of making a difference.

YOUNG: You can learn more about Professor Don Sadoway’s liquid metal batteries and the other energy grant winners at our website LOE dot org.



Click Here to Hear President Obama’s Speech at MIT

Dr. Sadoway and his research at MIT

The ARPA-E program at the Dept. of Energy


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