Investigation of the effect of coating on hydrogen charge and thermal characteristics in LaNi5 based metal hydrides

Abstract

The thermal and mass behavior of LaNi5 alloy, a metal hydride-based hydrogen storage material, modified with different surface coating types was investigated during the hydrogen storage process. Based on the experimentally measured thermal conductivity coefficients, four different sample groups were created: Sample 1 – uncoated LaNi5 powder, Sample 2 – copper-coated LaNi5, Sample 3 – copper/silver double-layer-coated LaNi5, and Sample 4 – silver-coated LaNi5. The thermal conductivity values of each sample were determined, and these data were evaluated in a three-dimensional model developed in COMSOL Multiphysics software. During the modeling process, the amount of hydrogen stored in the metal hydride reactor under different operating pressures (4 bar, 8 bar, and 12 bar) was calculated; the transient temperature distribution and hydrogen concentration profiles of the system were analyzed with time. It was shown that the coated samples – especially the Cu, Cu/Ag, and Ag coated samples – had higher thermal conductivities than the uncoated sample. This increase contributes to the shortening of the hydrogen absorption time and the limitation of local temperature increases, resulting in a more homogeneous temperature distribution in the system.

Keywords

• Hydrogen storage
• LaNi5 metal hydride
• alloy coating
• thermal conductivity

Kaynakça

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