Magnesium hydride (MgH2) with excellent hydrogen storage kinetics is important for
the wide application of hydrogen energy. Herein, to accelerate the sorption kinetics of
MgH2 and lower its dehydrogenation temperature, we design and prepare a carbon
film coated dual transition metal alloy, the Fe0.64Ni0.36@C composite with a coreshell structure, and employ it as an additive to synthesize MgH2–Fe0.64Ni0.36@C
system by ball-milling and hydriding combustion method. In contrast to pure MgH2, the
initial hydrogen release temperature of the MgH2–Fe0.64Ni0.36@C composite lowers
to 250°C from 480°C and the composite can absorb 5.18 wt% H2 within 20 min (150°C,
3 MPa H2). More importantly, the apparent activation energy of the dehydrogenation
for decomposition of Fe0.64Ni0.36@C-doped MgH2 reduced from 162.8 ± 8.3 kJ/mol
to 86.9 ± 4.6 kJ/mol. It is believed that the Fe@C and Mg2Ni/Mg2NiH4 formed on the
surface of Mg/MgH2 act as intermediates of electron transfer between Mg2+ and H–,
which synergistically enhanced the hydrogen absorption and desorption kinetics
properties of the MgH2. Moreover, the MgH2 co-doped with the multiple in-situ formed
active particles shows excellent cycling performance, indicative of potential application
in practical hydrogen storage in the near future.
Revised: September 30, 2020 |
Published: November 30, 2020
Citation
Ding Z., Y. Fu, L. Zhang, I.A. Rodriguez Perez, H. Zhang, W. Wang, and Y. Li, et al. 2020.IImprove hydrogen sorption kinetics of MgH2 by doping carbon-encapsulated iron-nickel nanoparticles.Journal of Alloys and Compounds 843.PNNL-SA-153605.doi:10.1016/j.jallcom.2020.156035