Improved hydrogen storage properties of MgH2 by nickel@nitrogen-doped carbon spheres
Improved hydrogen storage properties of MgH2 by nickel@nitrogen-doped carbon spheres
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镍@氮掺杂碳球改善MgH2的储氢性能
DOI：
10.1039/d0dt00025f
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发表时间：
2020
影响因子：
4
通讯作者：
Han Shumin
中科院分区：
文献类型：
--
作者：
Wang Yu;Ding Zhenmin;Li Xinjun;Ren Shuqin;Zhou Shuhua;Zhang Hongming;Li Yuan;Han Shumin
氢化镁由于其高重量容量（7.6wt%H2）和低价格而被认为是最理想的储氢材料之一。然而，其相对较高的工作温度和缓慢的动态一直阻碍其商业应用。本文采用化学还原法制备了纳米镍包覆氮掺杂碳球（Ni@NCS），并将其引入到镁中，通过高温燃烧和高能球磨制备了MgH 2-Ni@NCS复合材料。结果表明，MgH 2-Ni@NCS复合材料具有较高的储氢量和快速的吸放氢动力学，在623 K下，8 min内吸放氢量为5.7wt%，放氢量为4.3wt%。此外，在10次循环后，容量显示出可忽略的降低，表明MgH 2-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 2-Ni@NCS复合材料在60 min内仍吸收4.2 wt% H2，相比之下研磨MgH 2吸收0.9 wt% H2。储氢性能的改善归因于原位形成的Mg 2NiH 4诱导的MgH 2的脱氢以及碳材料有效地防止镁在吸氢/脱氢反应期间的团聚。
Magnesium hydride is considered to be one of the most desirable hydrogen storage materials due to its high weight capacity (7.6 wt% H2) 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 MgH2–Ni@NCS composite via hydriding combustion and subsequent high-energy ball milling processes. The results showed that the MgH2–Ni@NCS composite possessed high hydrogen storage capacity and fast absorbing/desorbing kinetics, absorbing 5.7 wt% H2 and desorbing 4.3 wt% H2 within 8 min at 623 K. Moreover, the capacity shows negligible degradation after 10 cycles, indicating that the MgH2–Ni@NCS composite has good cycling stability. Even at relatively low temperature (373 K), the MgH2–Ni@NCS composite still absorbed 4.2 wt% H2 within 60 min compared to 0.9 wt% H2 for milled MgH2. The improvement in hydrogen storage properties is ascribed to the in situ formed Mg2NiH4 induced dehydrogenation of MgH2 and effective prevention of the agglomeration of magnesium during the hydriding/dehydriding reaction by the carbon material.