Mg-Based Nanocomposites with High Capacity and Fast Kinetics for Hydrogen Storage

Abstract

Magnesium and its alloys have shown a great potential in effective hydrogen storage due to their advantages of high volumetric/gravimetric hydrogen storage capacity and low cost. However, the use of these materials in fuel cells for automotive applications at the present time is limited by high hydrogenation temperature and sluggish sorption kinetics. This paper presents the recent results of design and development of magnesium-based nanocomposites demonstrating the catalytic effects of carbon nanotubes and transition metals on hydrogen adsorption in these materials. The results are promising for the application of magnesium materials for hydrogen storage, with significantly reduced absorption temperatures and enhanced ab/desorption kinetics. High level Density Functional Theory calculations support the analysis of the hydrogenation mechanisms by revealing the detailed atomic and molecular interactions that underpin the catalytic roles of incorporated carbon and titanium, providing clear guidance for further design and development of such materials with better hydrogen storage properties.

Hydrogen storage characteristics of nanograined free-standing magnesium–nickel films

“…The basic storage mechanisms of hydrogen by physisorption and chemisorption as well as the importance of catalysts have been elucidated [3][4][5]. More recently, the benefits of using nanometer-sized materials have also been explored [6][7][8].…”

Catalytic De/Hydrogenation in Mg by Co‐Doped Ni and VOx on Active Carbon: Extremely Fast Kinetics at Low Temperatures and High Hydrogen Capacity

“…Ni and V are among the best metallic catalysts for this particular purpose, according to both theoretical prediction and experimental verifi cations. [ 6 , 17 ] From our previous research on the catalytic effect of metallic coupling of FeTi [ 11 ] and VTi, [ 13 ] It is reasonable to hypothesize the coupling of NiV should be much more effective on hydrogenation of Mg than Ni or V individuals. In this study, it is also demonstrated that the coupling of NiV is more effective than TiV, probably contributed to by the higher effectiveness of Ni compared with Ti.…”

“…In our previous work, we reported that metal couples, for example FeTi [ 11 , 12 ] and VTi, [ 13 ] were much more effective that the individual components with respect to kinetics. Furthermore, we also reported the effect of nanocarbons on increasing the practical hydrogen capacity [ 14 ] and the synergistic effect of metal coupling and nanocarbons; [11][12][13] it was reported that the MgVTi-CNTs system can achieve 5.1 wt.-% hydrogen within 5 min at a practically signifi cant low temperature of 150 ° C. However, the previously studied Mg-based systems have several disadvantages: i) relatively large amount of catalyst addition (10 wt.-%) that will reduce the theoretical hydrogen capacity and increase the cost of the Mg-based nanocomposites; ii) very long milling times (70 to over 100 h); and, iii) two-step synthesis of the composites, which will increase the possibility of oxidation and reduce the productivity.…”

Advances in the application of nanotechnology in enabling a ‘hydrogen economy’

“…Yao and colleagues [98,99] tried to develop Mg-based nanocomposites with nanoscale catalysts such as Fe and Ti that could enhance the kinetics of hydrogen absorption and desorption, and CNTs that could improve ambient hydrogen storage capacity. The results obtained for hydrogen absorption at 300°C are summarized in Fig.…”