Two new MgH2-based approaches for hydrogen storage proposed | The American Ceramic Society

Two new MgH2-based approaches for hydrogen storage proposed

Berkeley lab’s schematic of how high-capacity magnesium nanocrystals encapsulated in a gas-barrier polymer matrix provide a new and revolutionary hydrogen storage composite material. Credit: Jeff Urban; DOE.

Two separate groups have announced what sounds like somewhat similar magnesium hydride-based nanotechnology approaches to hydrogen storage.

One group, at the Lawrence Berkeley National Lab, has designed a new composite material for hydrogen storage consisting of nanoparticles of magnesium metal sprinkled through a matrix of poly(methyl methacrylate) (think Plexiglas). The group says the nanocomposite has several features, including selective gas permeability, blocking oxygen and water.

Researchers in the group say that with this design, the composite can quickly absorb hydrogen (up to 6 wt% of Mg, 4 wt% for the composite in less than 30 minutes at 200°C) to form magnesium hydride. They say it also can quickly reverse the process and release hydrogen, and the polymer barrier prevents the oxidation of the metal. In addition, these investigators say the material is pliable.

The group, whose work is being conducted as part of the DOE’s Hydrogen Storage Program, hopes that with this combination of properties, the storage material could be a major breakthrough in materials design for hydrogen storage, batteries and fuel cells.

Details of this work can be found in the paper (doi:10.1038/nmat2978), published in Nature Materials.

The other group is composed of chemists at the University of Glasgow working with the European Aeronautic Defense and Space Innovation Works group. The group is using nanotechnology to develop plans to improve the design and material composition of a special storage tank with the aim of making it so efficient that it will be feasible to use solid-state hydrogen in airplanes and cars.

Not many details are available, and it appears that this approach is still more conceptual than the Berkeley Lab group, but they say they plan on using a magnesium hydride, which has been modified at the nanoscale, to allow it to receive and release the hydrogen at fast rate.

This latter group, led by Duncan Gregory, professor of Inorganic Materials at the School of Chemistry at the University of Glasgow, has been working on finding a new material for a special storage tank for fuel cell applications under development by Hydrogen Horizons, a company about which there is little public information, but is described in these announcements as a start-up company. Reportedly, prototypes of the HH tank have used a lanthanum/nickel (LaNi5) alloy (for some discussion of LaNi5 storage, see this paper (pdf) about some ideas GM was working on several years ago).

Gregory says in a news release, “Using new active nanomaterials in combination with novel storage tank design principles presents a hugely exciting opportunity to address the considerable challenges of introducing hydrogen as a fuel for aviation. This collaboration between engineers and chemists and between industry and academia provides the pathway to achieve this.”

Previously, Gregory has done research on nitridic hydrogen storage materials. Currently, however, he seems to be focusing on a magnesium hydride material that he says will extend its longevity and release the hydrogen at a rate that could feed a fuel cell at energy densities that could power an airplane. Unfortunately, he doesn’t offer any hints about how his group is planning to combat the oxidation of the metal.

So, while the details are slim, the plans are bold: With a new tank structure, EADS hopes to fly an unmanned hydrogen-powered test plane in 2014 with a longer term view of introducing commercial airplanes powered by hydrogen.

Duncan and EADS IW have some funding from the Materials Knowledge Transfer Network — part of the U.K. Technology Strategy Board — and the Engineering and Physical Sciences Research Council. This will allow a student to carry out a four year Ph.D. project.

The University of Glascow’s website reports, “Once the technology has been proven in a small-scale demonstration, Prof. Gregory, Hydrogen Horizons and the EADS IW team intend to build a larger collaborative team with academic and industrial partners to seek large-scale funding from the U.K. and the European Union.”

EADS is comprised of Airbus, Astrium, Eurocopter and Cassidian.