Wang Yu, Ding Zhenmin, Li Xinjun, Ren Shuqin, Zhou Shuhua, Zhang Hongming, Li Yuan, Han Shumin
Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, PR China.
Dalton Trans. 2020 Mar 21;49(11):3495-3502. doi: 10.1039/d0dt00025f. Epub 2020 Feb 27.
Magnesium hydride is considered to be one of the most desirable hydrogen storage materials due to its high weight capacity (7.6 wt% H) and low price. However, its relatively high operating temperatures and slow dynamics have always hampered its commercial applications. In this paper, nano-nickel particle coated nitrogen-doped carbon spheres (Ni@NCS) were synthesized by a chemical reduction method and then introduced into Mg to form an MgH-Ni@NCS composite via hydriding combustion and subsequent high-energy ball milling processes. The results showed that the MgH-Ni@NCS composite possessed high hydrogen storage capacity and fast absorbing/desorbing kinetics, absorbing 5.7 wt% H and desorbing 4.3 wt% H within 8 min at 623 K. Moreover, the capacity shows negligible degradation after 10 cycles, indicating that the MgH-Ni@NCS composite has good cycling stability. Even at relatively low temperature (373 K), the MgH-Ni@NCS composite still absorbed 4.2 wt% H within 60 min compared to 0.9 wt% H for milled MgH. The improvement in hydrogen storage properties is ascribed to the in situ formed MgNiH induced dehydrogenation of MgH and effective prevention of the agglomeration of magnesium during the hydriding/dehydriding reaction by the carbon material.
氢化镁因其高储氢容量（7.6 wt% H）和低成本，被认为是最具潜力的储氢材料之一。然而，其相对较高的工作温度和缓慢的动力学特性一直阻碍着它的商业应用。本文采用化学还原法合成了纳米镍颗粒包覆的氮掺杂碳球（Ni@NCS），然后通过氢化燃烧和随后的高能球磨工艺将其引入镁中，形成MgH-Ni@NCS复合材料。结果表明，MgH-Ni@NCS复合材料具有高储氢容量和快速的吸/放氢动力学，在623 K下8分钟内可吸收5.7 wt% H并解吸4.3 wt% H。此外，经过10次循环后，该容量的降解可忽略不计，表明MgH-Ni@NCS复合材料具有良好的循环稳定性。即使在相对较低的温度（373 K）下，MgH-Ni@NCS复合材料在60分钟内仍能吸收4.2 wt% H，而球磨后的MgH仅吸收0.9 wt% H。储氢性能的改善归因于原位形成的MgNiH诱导的MgH脱氢，以及碳材料在吸氢/脱氢反应过程中有效防止镁的团聚。
