Effects of NbF5 addition on the de/rehydrogenation properties of 2LiBH4/MgH2 hydrogen storage system

2LiBH4/MgH2 system is considered as one of the prominent high capacity hydrogen storage materials. However, its absorption/desorption kinetics has to be further improved for the practical application. In this paper, we investigated the effects of NbF5 addition by ball milling on the de/rehydrogenati...

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Bibliographic Details
Published in:International journal of hydrogen energy 2012-09, Vol.37 (17), p.13147-13154
Main Authors: Xiao, Xuezhang, Shao, Jie, Chen, Lixin, Kou, Huaqin, Fan, Xiulin, Deng, Shuaishuai, Zhang, Liuting, Li, Shouquan, Ge, Hongwei, Wang, Qidong
Format: Article
Language:English
Subjects:
Additives
Alternative fuels. Production and utilization
Applied sciences
Complex hydride
Decomposition mechanism
Desorption behavior
Energy
Exact sciences and technology
Fuels
Hydrogen
Hydrogen storage materials
LiBH4
NbF5
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Summary:2LiBH4/MgH2 system is considered as one of the prominent high capacity hydrogen storage materials. However, its absorption/desorption kinetics has to be further improved for the practical application. In this paper, we investigated the effects of NbF5 addition by ball milling on the de/rehydrogenation properties of 2LiBH4/MgH2 system. The results show that NbF5 additive can lower the desorption temperature and improve the reaction kinetics of 2LiBH4/MgH2 system effectively. The 2LiBH4+MgH2+0.05NbF5 composite exhibits a good cycling de/rehydrogenation property. In first 15 cycles, the average hydrogen absorption and desorption capacities of the composite are about 8.97 and 8.33wt %, respectively. Desorption thermal analysis indicates that the activation energies of 2LiBH4+MgH2+0.05NbF5 composite are 100.3kJ/mol for first decomposition reaction and 127.5kJ/mol for second decomposition reaction. The possible mechanism of the effects of NbF5 additive for the improved de/rehydrogenation properties of 2LiBH4/MgH2 system is also discussed. ► NbF5 is a promising additive for improving the reversible hydrogen storage performances of 2LiBH4+MgH2 composite. ► NbF5 additive can reduce dehydrogenation temperature of 2LiBH4+MgH2. ► NbF5 also can improve hydrogen absorption/desorption kinetics of 2LiBH4+MgH2. ► The improved dehydrogenation is due to the complete transformation into MgB2/LiH.
ISSN:0360-3199
1879-3487
DOI:10.1016/j.ijhydene.2012.03.140