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In this study, the superior effect of RbF on reducing the hydrogen desorption operating temperature of the Li N H system was demonstrated. By doping 5 mol% RbF in the LiNH 2 LiH system, we obtain the lowest hydrogen desorption peak temperature (211 °C) at a heating rate of 5 °C/min, which is approximately 69 °C lower than that of the pristine LiNH 2 LiH system. Moreover, the system starts to desorb H 2 at 120 °C, which is the lowest hydrogen desorption onset temperature. The hydrogen desorption peak and onset temperatures can be further decreased by doping more RbF. It is proposed that the RbH produced during heat treatment improves the dehydrogenation properties of the RbF-doped LiNH 2 LiH sample. [ABSTRACT FROM AUTHOR]

In this study, we first examined the hydrogen release, uptake, and reversibility properties of the KLi 3 (NH 2 ) 4 -4LiH system and elucidated the influence of potassium cations' substitution into LiNH 2 on the hydrogen storage properties of the LiNH 2 -LiH composite. Our results show that mixing of the potassium cations into LiNH 2 can destabilize LiNH 2 , therefore decreasing the hydrogen desorption temperature and enhancing hydrogen desorption rate of the LiNH 2 -LiH system. Notably, the KLi 3 (NH 2 ) 4 -4LiH composite exhibits a superior cycling stability compared with the LiNH 2 -LiH composite prepared under the same condition. [ABSTRACT FROM AUTHOR]

In this study, the hydrogen desorption properties for the reactions between lithium hydride with different particle sizes and NH 3 (0.5 MPa, NH 3 /MH = 1 mol/mol) at 50–200 °C were systematically investigated to design the LiH–NH 3 hydrogen storage system with better kinetic properties. Moreover, various kinds of potassium compounds were also examined as potential catalysts to improve the kinetic properties of the hydrogen desorption reaction in the system. It is found that the kinetic properties of the hydrogen desorption in the LiH–NH 3 system are improved with the particle size of LiH reducing or the reaction temperature increasing. KBr, KCl, KF, and KOH are effective to enhance the kinetic properties, among which, KBr shows the best effect. [ABSTRACT FROM AUTHOR]

In this paper, the hydrogen storage properties of the LiNH 2 LiH system doped with K 2 TiF 6 were investigated and discussed. Interestingly, the hydrogen storage properties are significantly enhanced by introducing K 2 TiF 6 into the LiNH 2 LiH system. By doping 5 mol% K 2 TiF 6 in the LiNH 2 LiH system, we obtain the hydrogen desorption peak temperature (233 °C) at a heating rate of 10 °C min −1 , which is approximately 66 °C lower than that of the pristine LiNH 2 LiH system. Moreover, the system begins to desorb H 2 at 75 °C, which is approximately 124 °C lower than in the pristine LiNH 2 LiH system. The isothermal desorption kinetics at 250 °C and 300 °C clearly reflects the dramatically improved kinetic properties. Additionally, the reversibility of the LiNH 2 LiH system can be drastically enhanced by adding K 2 TiF 6 . We propose that the dehydrogenation property of the K 2 TiF 6 -doped LiNH 2 LiH sample is improved by the synergetic effects of K, Ti and F. [ABSTRACT FROM AUTHOR]

In this paper, the influence of multi-walled carbon nanotube (MWCNT)-doping on the hydrogen storage properties of the Li 3 N system was systematically investigated. Compared with the pure Li 3 N sample, the MWCNT-doped Li 3 N sample shows faster hydrogen absorption and desorption kinetics and a drastically improved cycling stability. Along with increasing MWCNT content, the hydrogen storage improvement becomes more apparent. When the MWCNT doping level reaches 10 mol%, the enhancement effect is significant. The improved hydrogen storage properties of the Li 3 N system by MWCNT-doping can be reduced to the physical effect of ball milling, the increased specific surface area and large pores as well as the good thermal conductivity of MWCNTs. [ABSTRACT FROM AUTHOR]

Interestingly, an obvious enhancement of the hydrogen storage property is achieved by introducing KF into the LiNH 2 –LiH system, while KCl, KBr or KI does not show obvious effect on improving the hydrogen storage properties of the LiNH 2 –LiH system. In comparison with that of the LiNH 2 –LiH composite, the hydrogen desorption curve of the LiNH 2 –LiH–0.05 KF composite becomes sharp and the dehydrogenation onset and peak temperatures are decreased by about 36 °C and 38 °C, respectively. The cyclic capacity and desorption kinetic of the LiNH 2 –LiH–0.05 KF composite in the tenth cycle are still much better than that of the LiNH 2 –LiH composite in the second cycle. Cyclic performance can be improved at least 4 times by addition of 5 mol% KF. Detailed structural investigations reveal that during the heat-treatment, the doped potassium fluoride can react with LiH and convert to potassium hydride, which induces the improvement in hydrogen storage properties of the LiNH 2 –LiH system. [ABSTRACT FROM AUTHOR]