Effect of ternary transition metal sulfide FeNi₂S₄ on hydrogen storage performance of MgH₂

Hydrogen storage is a key link in hydrogen economy, where solid-state hydrogen storage is considered as the most promising approach because it can meet the requirement of high density and safety. Thereinto, magnesium-based materials (MgH2) are currently deemed as an attractive candidate due to the potentially high hydrogen storage density (7.6 wt%), however, the stable thermodynamics and slow kinetics limit the practical application. In this study, we design a ternary transition metal sulfide FeNi2S4 with a hollow balloon structure as a catalyst of MgH2 to address the above issues by constructing a MgH2/Mg2NiH4-MgS/Fe system. Notably, the dehydrogenation/hydrogenation of MgH2 has been significantly improved due to the synergistic catalysis of active species of Mg2Ni/Mg2NiH4, MgS and Fe originated from the MgH2-FeNi2S4 composite. The hydrogen absorption capacity of the MgH2-FeNi2S4 composite reaches to 4.02 wt% at 373 K for 1 h, a sharp contrast to the milled-MgH2 (0.67 wt%). In terms of dehydrogenation process, the initial dehydrogenation temperature of the composite is 80 K lower than that of the milled-MgH2, and the dehydrogenation activation energy decreases by 95.7 kJmol(-1) compared with the milled-MgH2 (161.2 kJmol(-1)). This method provides a new strategy for improving the dehydrogenation/hydrogenation performance of the MgH2 material.(c) 2022 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Peer review under responsibility of Chongqing University