Fabrication of Multiple-Phase Magnesium-Based Hydrides with Enhanced Hydrogen Storage Properties by Activating NiS@C and Mg Powder

Abstract

Magnesium hydride is considered as a promising candidate for hydrogen storage; however, the sluggish kinetics and thermodynamic stability seriously obstruct its industrial applications. Hence, in order to improve the hydrogen storage performances of magnesium hydride, NiS@C additive was ball-milled with Mg powder to build NiS@C/Mg. The MgH2/Mg2NiH4 polyphase hydrides were in situ formed after hydrogenated activation and turned into Mg/Mg2Ni phases during the dehydrogenation process, establishing a cycle of hydrogen absorption and desorption. The NiS@C/Mg composite showed enhanced de/hydrogenation rates: it could quickly absorb 6.02 wt % H2 within 5 min at 250 °C and desorb 5.34 wt % H2 at 300 °C. Moreover, even at the temperature of 50 °C, it could reach 3.23 wt % hydrogen absorption capacity, and the apparent hydrogen desorption activation energy for MgH2 decreased to 60.45 kJ mol–1. It also delivered a high cyclic stability performance of 98.9% for hydrogen absorption and 98.5% for hydrogen desorption after 50 cycles. The enhanced de/absorption kinetics of NiS@C/Mg were ascribed to the synergistic effects of multiple-phase MgH2/Mg2NiH4 hydrides and the in situ formed MgS catalyst, and the existence of C also effectively prevented the passivation and agglomeration of multiple-phase particles. The method of in situ generating of multiple-phase hydrides and catalysts provides a new view for the preparation of high-performance hydrogen storage materials.

Hierarchical Structure Carbon-Coated CoNi Nanocatalysts Derived from Flower-Like Bimetal MOFs: Enhancing the Hydrogen Storage Performance of MgH2 under Mild Conditions

“…55 The Mao group obtained MgH 2 -10 wt % NiCl 2 and MgH 2 -10 wt % CoCl 2 nanocomposites by ball milling, which can only adsorb 2.6 and 0.8 wt % H 2 at 573 K for 30 min, respectively. 56 When the temperature drops to 523 K, the MgH 2 -10 wt % CoNi@C nanocomposite can still release 2.0 wt % H 2 for 60 min, which is better than the MgH 2 composites with Ni@C, 55 NiS@C, 30 TiH 2 , 57 and TiC x . 27 The activation energies of hydrogen absorption and desorption of MgH 2 -x wt % CoNi@C nanocomposites were calculated by the Johnson−Mehl−Avrami−Kolmogorov (JMAK) model and the Arrhenius theory, as shown below:…”

Nanointerface Engineering of Metal Hydrides for Advanced Hydrogen Storage

“…This Perspective focuses on Mg, for which many studies have been conducted because of its promise as a hydrogen storage material, and describes strategies for improving the thermodynamics of binary hydrides. Various approaches have been explored to improve the hydrogen sorption thermodynamics of Mg, including nanosizing, − ,,,,,, the use of catalysts, ,− and encapsulation in scaffolds. ,,,− ,− ,− , It is beyond the scope of this Perspective to cover all of the above, so only the effect of nanosizing is briefly described to distinguish it from the interfacial interaction in the composite structure that will be introduced later.…”

Dynamically Staged Phase Transformation Mechanism of Co-Containing Rare Earth-Based Metal Hydrides with Unexpected Hysteresis Amelioration

“…Utilization of hydrogen is the ultimate pathway to realize carbon neutrality. To better implement the deployment of a hydrogen economy, it is particularly critical to make breakthroughs in technologies related to fuel cell appliances, key technologies of hydrogen storage, and supply in hydrogen refueling stations. − …”