Road to the hydrogen highway

Posted: July 18, 2012 - 9:49am | Y-12 Report | Volume 9, Issue 1 | 2012

Photo used with permission of Toyota Motor Corporation.

Toyota plans to sell hydrogen-powered cars by 2015. To reach that goal, the world's largest automaker sought out Y‑12 to analyze the science behind making a hydrogen car work efficiently.

Hydrogen storage material, the fuel component for a hydrogen vehicle, is key to efficiency. Toyota developed a metal hydride, a solid chemical compound, that stores hydrogen and releases it under certain conditions. How slowly or quickly hydrogen is released from the hydride determines the vehicle's power and performance. To speed up, for example, hydrogen must be released rapidly. Y‑12's research is fundamental to Toyota's objective to create a hydrogen car that drives with the same level of convenience and performance as a combustion engine.

Toyota didn't come to Y‑12 because of the site's nuclear magnetic resonance spectrometer — every national research-and-development facility in the country has one. Toyota came because of Y‑12 chemist Ashley Stowe, an expert in hydrogen storage materials who worked with Toyota on a different project before joining Y‑12.

“I have a relationship with the company, and they wanted to continue that relationship,” he said.

Using nuclear magnetic resonance spectroscopy, Stowe analyzes the hydride samples the car company provides. The spectrometer gives him information about the samples' chemical environment — the interactions within the material, what impurities are present, how fast the atoms move around in chemical reactions. He uses the instrument to gather data on whether Toyota's proprietary techniques have modified the samples in a way that brings about a more favorable hydrogen release.

“My primary responsibility is to analyze materials, but we also discuss directions of the science,” Stowe said. “We talk about the different ways we can do the research, modify the research and use the tools I have to figure out what's going on in the material itself. There are certainly areas of collaboration.”

Although little funding is provided for his analyses and he expects his work for the car manufacturer to grow only in the tens of thousands of dollars, he is an important colleague in scientific discoveries, even sharing a patent for a prior project with his Toyota counterpart, Rana Mohtadi. “The materials-related work with Y‑12 is essential for determining and understanding hydrogen-storage-material properties so improved hydrogen-fuel-cell car systems could be developed,” said Mohtadi, a scientist at the Toyota Research Institute of North America in Ann Arbor, Mich.

The researchers will have to jump many hydrogen hurdles before fuel cell vehicles fill the roadways, including reducing cost, improving fuel cell durability and the ability to store large volumes of hydrogen fuel, and building nationwide fueling stations. “It's definitely a race to build a more efficient vehicle,” Stowe said. “For there to be a breakthrough, there has to be a perfect storm of high-priced gasoline, political pressure and technological advances that make a hydrogen-powered car economical.”

Whatever the outcome, Stowe sees this work as an opportunity for Y‑12 to diversify its research portfolio and engage in development of alternative energy research that may lessen America's dependence on foreign oil.

“This funding allows me to dabble in an area that I find extremely interesting,” he said. “It's not a lot of money. That's not the point. I want people to know that Y‑12 has the expertise and capabilities to help answer the most difficult and practical questions facing the nation — even though it's outside of the nuclear environment, outside of what everybody thinks it is we do.”

Car Talk

Hydrogen, the most plentiful element in the universe, doesn't exist as a gas on Earth. Hydrogen gas is needed to fuel hydrogen-powered cars. Although this gas can be produced a number of ways, Toyota scientists have focused their efforts on making hydrogen gas that is stored in a solid chemical compound. Oftentimes, this compound, known as a hydrogen storage material, contains a lot of metal hydride. When the hydride is heated, hydrogen is released as a gas and separates from the storage material. The gas is stored in a fuel cell. When the gas mixes with oxygen, the fuel cell converts chemical energy into electrical energy. Fuel cell cars ultimately are electric cars, but they use hydrogen as fuel, have a far greater driving range and don't require lengthy recharging. Known as a clean fuel, hydrogen's only byproduct is water. Water you can actually drink.