La-Ni-H metal hydride system aging effects identification

• An accelerated aging method was developed to predict the life-cycle of the metal hydrides for space applications. • After 12 years, the predicted LaNi 5 ′s capacity degradation is around 0.152 % (operating at 30 °C) to 0.415 % (operating at 50 °C). • Nanostructuring of the material is the main cause of its degradation. • This work offers designing strategies for prolonging the metal hydrides’ life to the manufacturers. One of the most commonly used materials for sorption compression in space applications is based on the La-Ni-H system. The degradation of the material properties and, therefore, the system lifetime is of great importance for the final success of a potential space mission. Considering that satellites and other equipment that have to operate in space are expected to be fully functional for more than 10 years, in this work, an accelerated aging method is designed and carried out to predict the La-Ni-H system properties after 12 years under specific operating conditions. For this test, several specimens of fully hydrogenated LaNi 5 are exposed to specific hydrogen pressures (i.e., 20, 35, 58 and 96 bar) at different temperatures (i.e., 50, 90, 130 and 160 °C) for a duration of 90 days. Sievert’s type apparatus, synchrotron radiation powder X-ray diffraction (SR-PXD), quasi-elastic neutron scattering (QENS), scanning electron microscopy (SEM), and small-angle X-ray scattering (SAXS) methods are used to investigate the material aging and its impact on the material chemical and microstructural properties.