Continuum simulation of hydrogen storage with complex hydride at nanometer length scale using Small Angle Neutron Scattering (SANS) measurements to estimate volumetry measurement at engineering length scale
Date:
Topic: Combination of in situ SANS and continuum simulation to analysize hydrogen diffusion in nanoscale and its imapact of storage performance in the engineering length scale.
Authors
Arnab Majumdar, Martin Müller, and Sebastian Busch
Abstract
One of the major challenges in realizing a hydrogen-based economy is finding an efficient and safe method for hydrogen storage. Chemical storage using complex hydrides presents a promising solution and characterizing the hydrogen storage process at various length scales is crucial for optimizing this approach. At the nanometer length scale and below, neutron scattering emerges as a powerful non-destructive technique for revealing sub-surface material information [1]. Notably, neutron scattering is particularly advantageous for studying hydrogen storage due to hydrogen’s significant scattering interaction with neutrons. Additionally, neutrons scatter differently depending on the isotope, allowing deuterium to be used in place of hydrogen for enhanced insights into the hydrogen storage process.
Among the different neutron scattering techniques, Small Angle Neutron Scattering (SANS) is suited for characterizing structures at the nanometer length scale, which is the chosen length scale of interest for this work. Featureless SANS patterns obtained from hydrogen storage material prompted a novel in situ SANS approach, revealing clear features during the hydrogen absorption and desorption processes [2]. The in situ measurements confirm the occurrence of the hydrogen storage process but measurements alone could not provide complete details about the underlying processes.
Computer simulations were performed using various models, and new methods were developed to calculate the corresponding scattering patterns [3]. The most suitable model described the nanoscopic structure using the probability distribution of different compounds. The evolution of initial to final probability distribution was modelled according to different chemical kinetic models. The probabilistic approach qualitatively reproduces the experimental data, suggesting the presence of trapped gas at the nanometer scale during desorption. This key insight enables an estimate of volumetric performance at the engineering scale, which shows a good match with experimental observations.
References:
[1] Hosseini et al., doi:10.3390/hydrogen2040024
[2] Aslan et al., doi:10.3233/JNR-190116
[3] Majumdar et al., doi:10.3390/ijms25031547