Berlin 2024 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 29: Poster II

MM 29.12: Poster

Tuesday, March 19, 2024, 17:00–19:00, Poster B

Experimental determination of material expansion upon hydrogenation of interstitial metal hydrides — •Gerd Stahlkopf — Hereon, Institute of HydrogenTechnology, Geesthacht, Germany

Hydride-forming materials (MH) are increasingly attractive since they provide efficient and safe hydrogen storage at mild temperatures and low pressures, offer a high volumetric storage density and are very interesting for stationary storage systems. Although the volumetric density of MH systems are relatively high, the MH-storage system needs to be optimized (maximum hydrogen storage capacity, efficient tank designs, longer system lifetime) and their practical application show relevant technological challenges. One of the main challenges for the application of MH as the storage medium is the resulting stress on the container walls when hydrogen is absorbed since the MH bed increases its volume by about 30 %. This "swelling" phenomenon is the bottleneck when designing a hydrogen storage system based on metal hydrides. Despite many efforts to avoid the by the swelling caused stress there is a lack of basic understanding of this swelling effect at the microscopic scale evolving upon the hydrogenation/dehydrogenation process over the cycles. This work focuses on the interdependency between the changing properties of the powder bed in- and ex-situ (e.g. particle size distribution, porosity, friction) and the stress caused by the swelling of MH over titration cycles. A deep understanding of the effect of powder bed parameters on the swelling stress will improve MH vessel designs and a proposed model. The changing characteristics of the MH-powders are investigated.

Keywords: hydrogen storage; metal hydride; x-ray; powder; friciton