Metal-N-H system has attracted much attention as a new family of H-storage since Chen et al. reported that Li3N reversibly absorbed/desorbed a large amount of hydrogen (10.4 wt.% ) [1]. Recently, LiBH4 was found to tremendously improve the hydrogen storage properties of Li-Mg-N-H system by weakening N-H bond [2]. Meanwhile, LiBH4 is a high-efficiency microwave absorber which can realize rapidly heating under microwave so as to release hydrogen promptly [3]. In this paper, the effect of microwave irradiation on the hydrogen desorption properties of Li-N-H system doped with LiBH4 were systematically investigated. The results show that Li-N-H system doped with LiBH4 can be heated rapidly under microwave irradiation. For example, the 7.6wt% LiBH4 added sample was heated up to 500 oC in 5min under microwave of 400W. Unlike pure LiBH4 which has a sluggish heating rate below 380K under microwave [3], the LiBH4 doped Li-N-H sample can be rapidly heated up from room temperature. Further study indicate it is the solid solution phase (LiNH2)x(LiBH4)(1-x) formed during the ball milling process that acts as a more effective microwave absorber than LiBH4. Furthermore, the isothermal desorption kinetics of Li-N-H+7.6wt%LiBH4 sample at 250�C under microwave heating is much faster than that under furnace heating, which indicates that microwave irradiation can greatly improve the desorption kinetics of Li-N-H system doped with LiBH4. These results demonstrate that the microwave heating is an effective technology for improving the hydrogen desorption kinetics of the Li-N-H/LiBH4 composite with the high energy efficiency.Keywords:  Hydrogen storage; Microwave; Metal amide; LiBH4References [1]    Chen, P.; Xiong, Z.; Luo, J.; Lin, J.; Tan, K.L. Nature 2002, 420, 302.[2]    Jianjiang Hu et al.. Chem. Mater. 2008, 20, 4398-4402.[3]    Y. Nakamori et al..Journal of Alloys and Compounds.446-447 (2007) 698-70.  Acknowledgment  The authors thank Instrumental Analysis and Research Center of Shanghai University for their support of materials testing and research. This work was financially supported by Natural Science Foundation of China (21071149) and Innovation Program of Shanghai Municipal Education Commission (12YZ012).

Effect of microwave irradiation on the hydrogen desorption properties of Li-N-H system doped with LiBH<sub>4</sub>

247th National Meeting (2014)

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Effect of microwave irradiation on the hydrogen desorption properties of Li-N-H system doped with LiBH4

Effect of microwave irradiation on the hydrogen desorption properties of Li-N-H system doped with LiBH₄