Profile
As part of the Helmholtz Research Programme "Advanced Engineering Materials", we are developing novel nanostructured materials for the storage of hydrogen. Unlike the storage of gaseous hydrogen in high-pressure tanks or its storage in liquid form, we employ a method in which the hydrogen is chemically bound in a solid material by an exothermic reaction during charging. These so-called solid-state storage systems are based on light-metal hydrides or hydride composites and offer an especially high level of safety. Major applications include hydrogen stores for future zero-emission automobiles, where such systems will be able to offer a high storage capacity relative to volume and weight.
Scheme of the Reactions taking place in a "Reactive Hydride Composite"
In comparison with the other hydrogen storage alternatives like compressed gas or liquid hydrogen storage, solid state storage tanks can reach the highest energy efficiency. Several light metals and light metal composites can be hydrogenated at rather low hydrogen pressures. During the hydrogenation the tank releases heat. The same amount of heat has to be provided during desorption. To achieve the highest possible energy efficiency it is required that the hydrogen reaction enthalpy / heat is adjusted to the process heat generated during operation. For this it is essential to find new approaches to tailor the enthalpy of reaction of hydrides, i.e. the amount of heat required to release a certain amount of hydrogen. In 2004 a breakthrough in hydrogen storage technology was achieved by the development of the “Reactive Hydride Composites” by scientists of the Helmholtz-Zentrum Geesthacht as well as of the HRL Laboratories independently. Both groups were able to show that the reaction heat can be tuned significantly by the approach of combining two hydrides in nanocomposites.
Potential of Solid State Hydrogen Storage
Our work focuses primarily on the following areas:
- The investigation of light-metal hydrides, complex hydrides, reactive hydride composites and suitable catalysts capable of offering the requisite hydrogen storage density and reaction kinetics for the applications in question.
- The low-cost production, by means of high-energy grinding, of nanocrystalline materials for hydrogen storage and the development of a corresponding engineering process for industrial use.
- The test of the materials in larger powder beds and test tanks under application oriented conditions as well as the optimisation of the tank design for complex hydrides and reactive hydride composites.
The Helmholtz-Zentrum Geesthacht is responsible for FuncHy (Functional Materials for Mobile Hydrogen Storage), a Helmholtz initiative involving close cooperation with the Karlsruhe Institute of Technology KIT, along with the Leibniz Institut für Festkörper- und Werkstoffforschung Dresden, the Vrije Universiteit Amsterdam in the Netherlands, and Empa in Dübendorf, Switzerland. The project focuses on the search for and study of optimised storage materials featuring a capacity in excess of five per cent by weight and, with respect to the application, a suitably rapid uptake and release of hydrogen at normal pressure and temperatures below 150 °Celsius. The Helmholtz-Zentrum Geesthacht also coordinates the Marie Curie Research Training Network COSY, which comprises 13 European partners, and the European Collaborative Project FLYHY (5 partners). The Helmholtz-Zentrum Geesthacht likewise is a partner in the European Integrated Project NESSHY as well as in the German NOW Project "Development, Upscaling and Testing of Nanocomposite Materials for Hydrogen Storage" (in the frame of the German-Chinese Sustainable Fuels – Partnership).