Environmentally friendly hydrogen storage tanks made from recycled metal

Titanium-iron alloys are particularly promising for hydrogen storage as they can absorb large quantities of hydrogen. However, the production costs of such materials have been very high until now. For this reason, the Federal Institute for Materials Research and Testing (BAM) is researching the use of recycled raw materials as part of a federal hydrogen lead project with the intent of significantly reducing material costs and putting the technology on a broader footing.

In addition to gaseous storage in conventional pressurised storage tanks, hydrogen can also be stored in metal compounds. The hydrogen is absorbed by the alloy like a sponge: On contact with the surface, the H2 molecules split into individual atoms, penetrate the lattice structure of the metal, accumulate in gaps and defects and combine with the material to form so-called hydrides.
This technology not only allows hydrogen to be stored very densely but also safely, as the hydrogen atoms remain bound in the metal and cannot escape uncontrollably. In addition – contrary to the use of conventional storage tanks – neither high pressure nor extremely low temperatures are required. If the hydrogen is needed, it can be released again as a gas using heat, e.g. from fuel cells.

‘GreenH2Metals’ joint project researches titanium-iron materials

In the ‘GreenH2Metals’ joint project, BAM is researching how well the recycled titanium-iron materials can absorb and release hydrogen and is therefore making an important contribution to the further development of hydrogen technology and the circular economy – key building blocks for the energy transition.
Researchers use special measuring methods and take a closer look at the inner structure of the materials. Using computer simulations, they are particularly investigating the role that defects in the lattice structures play in the long-term stability of the materials and their storage capacity. The aim is to develop a prediction model for how impurities affect the properties of the materials during the recycling process. BAM is also researching how the material can be handled safely, especially in a powdery processing state.
In addition to BAM, the Rheinisch-Westfälische Technische Hochschule Aachen, the Ruhr University Bochum and the Max Planck Institute for Sustainable Materials are involved in the joint project, which is coordinated by the Helmholtz Centre Hereon. GreenH2Metals is funded by the Federal Ministry of Education and Research (BMBF) with about 3.3 million euros.
Source: idw/BAM