Enhanced Hydrogen Storage Properties of Li-RHC System with In-House Synthesized AlTi3 Nanoparticles

Abstract

In recent years, the use of selected additives for improving the kinetic behavior of the system 2LiH + MgB2 (Li-RHC) has been investigated. As a result, it has been reported that some additives (e.g., 3TiCl3·AlCl3), by reacting with the Li-RHC components, form nanostructured phases (e.g., AlTi3) possessing peculiar microstructural properties capable of enhancing the system’s kinetic behavior. The effect of in-house-produced AlTi3 nanoparticles on the hydrogenation/dehydrogenation kinetics of the 2LiH + MgB2 (Li-RHC) system is explored in this work, with the aim of reaching high hydrogen storage performance. Experimental results show that the AlTi3 nanoparticles significantly improve the reaction rate of the Li-RHC system, mainly for the dehydrogenation process. The observed improvement is most likely due to the similar structural properties between AlTi3 and MgB2 phases which provide an energetically favored path for the nucleation of MgB2. In comparison with the pristine material, the Li-RHC doped with AlTi3 nanoparticles has about a nine times faster dehydrogenation rate. The results obtained from the kinetic modeling indicate a change in the Li-RHC hydrogenation reaction mechanism in the presence of AlTi3 nanoparticles.

Reversible Hydrogen Storage Performance of 2LiBH4-MgH2 Enabled by Dual Metal Borides

“…By contrast, an ultralong period of 12 h is required for the complete H 2 desorption of 2LiBH 4 -MgH 2 composite even at a temperature as high as 420 °C (Figure c) and a slight increase in the nucleation time would be observed in the subsequent H 2 desorption process due to the increase in particle sizes during cycling. In addition, the H 2 desorption capacity is also reduced to 9.5 wt % after only five cycles of H 2 storage process, which could be attributed to the particle aggregation upon heating at high temperatures and incomplete hydrogenation of the dehydrogenated products, corresponding to 88.8% of the initial capacity (Figure d). , By prolonging the hydrogenation time to 20 h, only a slight capacity decay of LBMH could be observed (Figure S6), which confirms the sluggish hydrogenation kinetics of LBMH and catalytic effect of in situ formed MgNi 3 B 2 and CoB in enhancing the hydrogen adsorption performance of 2LiBH 4 -MgH 2 composite. Compared with the previously reported 2LiBH 4 -MgH 2 composite catalyzed by Ni-based catalysts, the capacity retention and the reversible capacity of LBMH-NiCo@NC are among the best Ni/Co-based catalyst-doped 2LiBH 4 -MgH 2 composite.…”