Enhancement of Ti-Cr-V BCC alloys on the dehydrogenation kinetics of Li-Mg-N-H hydrogen storage materials

Abstract

The hydrogen storage properties of a Li-Mg-N-H material doped by a 4 mol.% Ti 3 Cr 3 V 4 body centre cubic (BCC) alloy hydride and prepared with a ball-milling method were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Sievert's technology test. The results show that the Ti 3 Cr 3 V 4 BCC alloy hydride/Li-Mg-N-H composite has good reversible hydrogen storage properties. The dehydrogenation kinetics of the Li-Mg-N-H system can be greatly improved by doping the Ti 3 Cr 3 V 4 BCC alloy hydride. The composite desorbed 4.1 wt.% hydrogen in the first 60 min at 473 K under 0.1 MPa pressure, but when without the BCC alloy addition, only 3.0 wt.% hydrogen was desorbed under the same dehydrogenation condition. It can be deduced that the Ti 3 Cr 3 V 4 BCC alloy uniformly distributed in the Li-Mg-N-H substrate could decrease the activating energy of hydrogen molecules to H atoms and increase H diffusion paths in the composite, enhancing the dehydrogenation kinetics of the Li-Mg-N-H system.

High-temperature failure behaviour and mechanism of K-based additives in Li–Mg–N–H hydrogen storage systems

“…See DOI: 10.1039/c4ta00025k compounds. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] In particular, K-based compounds exhibited superior catalytic activity in the Mg(NH 2 ) 2 -2LiH system. The peak temperature for hydrogen release from the Mg(NH 2 ) 2 -1.9LiH-0.1 KH sample was 132 C, which is 54 C lower than that of the Mg(NH 2 ) 2 -2LiH sample.…”

The kinetics of lightweight solid-state hydrogen storage materials: A review

“…The properties of LieMgeNeH doped with the Ti 3 Cr 3 V alloy markedly reduced the activation energy of the hydrogen molecules and improved the diffusion path of hydrogen in the material, thus enhancing the desorption kinetics of the LieMgeNeH material. The Ti 3 Cr 3 V 4 alloy/LieMgeNeH composite desorbed 4.1 wt% H 2 ; without the alloy, only 3.0 wt% H 2 was desorbed in the first hour at a temperature and pressure of 473 K and 0.1 MPa, respectively [113].…”

Li–Mg–N–H-based combination systems for hydrogen storage

“…Chen et al [107] introduced different carbon materials such as single-walled carbon nanotubes (SWNTs), multi-walled carbon tubes (MWNTs), graphite and activated carbon into the Mg(NH 2 ) 2 -2LiH mixture as additives, and found that about 90% of the hydrogen capacity can be released at 200 • C in 20 min from the sample with addition of SWNTs while less than 60% of the hydrogen capacity was released from the pristine sample. In addition, many chemicals, such as NaH, NaNH 2 , TiN, TiF 3 , TaN, Li 3 N, V, V 2 O 5 , VCl 3 , Ti 3 Cr 3 V 4 hydride and graphite-supported Ru nanoparticles were also added as catalysts for improving the kinetics of the Mg(NH 2 ) 2 -2LiH system [108][109][110][111][112][113][114]. But the operating temperatures for hydrogen absorption/desorption are still far from the practical requirement.…”