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Levi Thompson: Building clean energy from the atom up

by Lynne Raughley

March 11, 2008

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Chemical Engineering professor Levi Thompson pictured with a microfuel cell. Thompson is engrossed in one of the most society's most pressing engineering problems: finding ways to generate clean energy and reduce polluting emissions from cars and other products.

One among many definitions of research is "A second or repeated search": that is, to re-search. Rare though it is, this usage rings true to Levi Thompson, Professor of Chemical Engineering in the University of Michigan's College of Engineering.

Thompson is engrossed in one of the most socially important realms of engineering: finding ways to generate clean energy and reduce polluting emissions from autos and other products. He's a leader in the development of hydrogen fuel cell technology. And his work in catalysis could lead to solutions for our most pressing problems—energy, health care, and water.

Thompson runs several laboratories in U-M's H. H. Dow Building, and leads a team of fifteen graduate students, plus undergrads and post-doctoral fellows. Technically speaking, Thompson and his colleagues structure and restructure atoms and molecules, in search of catalysts that might be used in products that reduce harmful emissions, or in smaller, less expensive hydrogen fuel cells for automobiles.

Most of professor Thompson's work occurs at the microscopic level. The term of art is "nanostructured technologies," super-tiny constructions at the atomic and molecular level. He says, "We have these assemblies of atoms, and the same elements and atoms—the exact same number and composition—function differently depending on how they're assembled." By rearranging these molecular structures, Thompson and his team can change the way fuels, batteries, and chemicals operate.

Take, for instance, a device his team invented. It is a cube made from thin sheets of metal, about two and a half inches per side, designed to help reduce or eliminate harmful nitric oxide (N0) emissions from a car's engine. "Currently, the strategy for getting rid of N0 involves having a second tank of something on the car—if I were driving a diesel vehicle, I might have urea, for example." One surface of his lab's new device contains a thin membrane that delivers a hydrogen-generating catalyst. "What we plan to do is take a tiny bit of that diesel fuel and convert it to hydrogen, which will be our reductant for the NO. Then everything'll be perfect."

Perfect?

Thompson laughs. "Well, not perfect, but it'll be better." He continues, "That's a good point, because in some regards that's what engineering is all about, making things better and better. The quest is not necessarily for perfection."

Indeed, a lot of the "re-search" that Thompson's team performs is just gritty trial and error.

"Most of what we try to do probably will not work," he asserts. But they try it, knowing that even if an experiment doesn't yield the product or result that he and his colleagues are seeking, "Every new piece of information adds to the total database, and every experiment is helpful in some regard—it helps you get to the product that you want."

One of Thompson's strengths as a researcher is that "the product he wants" is more than an interesting test result. His work begins and ends at the nano-level, but along the way, his team gets into macro-sized structures.

"A lay person's probably going to say, 'Well, you do energy.' The reality is, those of us doing energy have to focus on basic materials work—at the device level, the systems level, and the megasystems level." In order for Thompson's catalysis work to succeed, he has to find ways to make it work in devices, that is, real-world products.

"If I give you a battery that has a particular form factor, you're going to say, 'Well, what can I do with this?' So I need to put it into a device." When the battery is functioning in a device, you have a system. Connect the device to, say, a wireless Internet setup, and you have a megasystem, a system of systems.

What makes a good megasystem? It depends on who's using it. Thompson doesn't want systems that have applications only in the lab. In the real world, consumers will only accept products if they have a certain set of what Thompson refers to as "performance characteristics," and therefore he must look beyond purely scientific considerations.

A problem is not actually solved if the product that delivers the solution is too expensive, or is otherwise unattractive to consumers.

He describes the current limitations of hydrogen-powered automobiles as a for instance: "If I tell you, 'I'll give you a car that's going to cost three times what a car costs now,' is that going to be good? Or, 'I'm going to provide you with a vehicle that every three years requires a major service'—say it's built into the cost, but every three years I'm going to have to remove the fuel cell stack and put a new one in." He shakes his head. "The average person, who's used to running a car for ten years, won't accept it."

In fact, consumers are generally leery of drastically new automotive technologies when they're part of the power train. Thompson says, "If you're telling me [you're concerned about] the cup holder, you're telling me you don't want to worry about what kind of technology is in the engine."

Engineers like Thompson can't change this buying behavior. Instead, they must find a way to provide clean technology at costs people are willing to pay. China, for example, is poised to become the world's biggest polluter, and it isn't likely to sacrifice economic growth for environmental considerations. "We can't add a thousand dollars per car, because they're trying to sell cars for a thousand dollars. We probably have to provide something that costs fifty or a hundred bucks." It might sound like a pipe dream, but Thompson says no. "It is possible, but to get there is going to require a huge investment." He grins. "I think we could figure it out, with a trillion dollars."

Though the obstacles to clean cars are daunting, there's hope in the notion that energy is a problem that can be solved, that the stumbling blocks are financial, rather than the absolute limits of the material world.

"What's beautiful here is, I don't think we know that the limits are. We might focus on nanomaterials for energy, and find something that improves health care, or water resources, or solves some other problems."

"It's almost intoxicating," he adds, "to think about what else we might learn."

"Faculty at Work" writer Lynne Raughley lives in Ann Arbor Michigan with her husband and their three-year-old son.