Nanoscopic bubble formation during desorption from hydrogen storage material: Insights from Small Angle Neutron Scattering and computer simulations
Date:
Topic: Analysis of hydrogen storage using Small Angle Neutron Scattering and computer simulations complementarily
Authors
Arnab Majumdar, Martin Müller, and Sebastian Busch
Abstract
The use of fossil fuels to satisfy the ever-growing energy demand is expected to cause an irreversible increase in temperature. Alternative fuels like hydrogen can be part of a solution to this problem. However, the low volumetric density of hydrogen in gas and liquid phases incurs problems related to storage [1]. To circumvent this problem, the chemical storage of hydrogen using a complex hydride system can be opted for. Amongst several options in the class of complex hydrides, a mixture of Mg(NH2)2, LiBH4, and LiH was chosen in this work to investigate using Small Angle Neutron Scattering (SANS) experiments and simulations [2].
In situ SANS measurements were performed to investigate the hydrogen storage process on the nanometer length scale. A direct deduction of the process or structure in real space from the measured data is not possible due to the phase problem. Therefore, several models were proposed based on different hypotheses and the in situ SANS data was calculated from the simulation for comparison with experiments, accounting for all relevant instrument details [3–5]. Among all models, the calculated data from the probabilistic model are most compatible with the measured data. The probabilistic model generated representative nano-structures of absorbed and desorbed states.
Using the probabilistic model and in situ SANS data, it was found that hydrogen gas must be partially entrapped on the nanometer length scale during desorption. Using the findings on the nanometer length scale, the volumetry performance related to the millimetre length scale was predicted and a good match with the measurement was found.
References:
[1] Pistidda et al., doi:10.3390/hydrogen2040024
[2] Aslan et al., doi:10.3233/JNR-190116
[3] Mühlbauer et al., doi:10.1016/j.nima.2016.06.105
[4] Karge et al., doi:10.1107/S1600576717011463
[5] Majumdar et al., doi:10.3390/ijms25031547