in2science #3

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Institute of Materials Research

The department


Research Under High Pressure: Anna-Lisa Chaudhary

Anna-Lisa Chaudhary works with new materials for hydrogen tanks

Anna-Lisa Chaudhary

Photo: private, Illustration: Maren Wilfert

The experimental setup is brand-new: a wardrobe-sized metal frame with many pipes, valves and pressure indicators. Visibly excited, Ann-Lisa Chaudhary goes through the core components: a compressor compresses hydrogen gas to 2000 bar. A system consisting of pipes and valves regulates and distributes the hydrogen. Then there is as a small, bulky metal cylinder that can withstand high pressures and temperatures. “That is the sample chamber,” the materials researcher says. “We use it to measure to what extent certain nanomaterials are suitable for storing hydrogen.”

Many experts consider hydrogen a crucial component in the energy revolution. It helps store solar and wind energy so that it can also be supplied during night-time hours and during calm weather. In addition, fuel cell automobiles can be driven free of emissions if using hydrogen – and with a considerably higher cruising range than with battery-operated vehicles. There is, however, a need to do more research and development: the tanks for hydrogen cars are currently still too clunky and large. At the HZG’s Institute of Materials Research, Ann-Lisa Chaudhary works on an alternative to the conventional pressure tanks – nanomaterials that store hydrogen by chemically binding to it.
“It may sound surprising, but in principle, much more hydro gen can be accommodated in a solid body than in a pressure tank,” Chaudhary points out. She had already begun her work in her homeland of Australia.

"I was fascinated by environmental topics even as a kid"

the 39-year-old reminisces. Her father is British and her mother comes from the Philippines. She initially studied chemical engineering, after which she completed her doctorate in physics at Curtin University in Perth where she began her hydrogen storage research. She received a job offer from Geesthacht even before she completed her dissertation. She secured a position as a post-doctoral researcher and she had a concrete goal: the expert was to study materials that could bind hydrogen at high pressures – a very promising class of materials.

Chaudhary didn't need to mull it over for long.

“Germany is clearly investing more in developing renewable energy than the coal country of Australia,” she says. “The research possibilities in Geesthacht are fantastic.”

In 2013, she packed up her two kids, who were four and five at the time. “Initially I had some reservations because the schools are entirely in German here,” the researcher says. “But within a few months, my children adjusted and now they speak better German than English.”

Chaudhary was already familiar with Germany before accepting the position at the HZG as she’d visited her friends here several times. “That was always in winter though, so perhaps I had a somewhat skewed picture,” she says, smiling. Since then, however, she‘s become acquainted with the country’s sunnier side too.

"I really like it - especially the educational and healthcare systems - and of course the working conditions."

The team she works with is international and mainly communicates in English. “Sometimes I wish German was spoken more often,” the scientist points out. “Then I’d have more of an opportunity to practice the difficult grammar.”

She began her work on the high-pressure experiment back in 2013 and the facility has been finished since May 2016. It is located in a building specially designed for hydrogen storage experiments. “My experimental set-up is unique worldwide,” says Chaudhary, not without pride. Her team is still tweaking the software, but the experiments should be underway in 2017. They will then test metal hydrides based on magnesium, boron or aluminium for their suitability at pressures of up to 2000 bar and temperatures of up to 500 degrees.

The possible advantages are that, in principle, more hydrogen should be able to be stored under high pressure than in metal hydride tanks that function at normal pressure. Refuelling quickly should also be possible. The aim is to develop a hydrogen tank that can be filled just as quickly as a gasoline or diesel tank today – that is, within a few minutes.

„We’re looking for a material that can store as much hydrogen as possible at high pressures and at moderate temperatures,” the researcher explains. “I would love to test such a material in a tank prototype.” Chaudhary’s post-doc appointment runs out in July of 2017 however. “I’d really like to stay here and continue my research at the HZG,” she says, smiling. “And I don’t think my children would have anything against that.”

Author: Frank Grotelüschen
Portrait from in2science #3 (January 2017)