Local defects enhanced dehydrogenation kinetics of the NaBH(4)-added Li-Mg-N-H system.
A mechanistic understanding on the enhanced kinetics of hydrogen storage in the NaBH(4)-added Mg(NH(2))(2)-2LiH system is provided by carrying out experimental investigations associated with first-principles calculations. It is found that the operating temperatures for hydrogen desorption of the Mg(NH(2))(2)-2LiH system are reduced by introducing NaBH(4), and the NaBH(4) species seems almost unchanged during dehydrogenation/hydrogenation process. First-principles calculations reveal that the presence of NaBH(4) in the Mg(NH(2))(2)-2LiH system facilitates the formation of Mg vacancies in Mg(NH(2))(2). The appearance of Mg vacancies not only weakens the N-H bonds but also promotes the diffusion of atoms and/or ions, consequently resulting in the improvement of the reaction kinetics of hydrogen desorption/absorption of the NaBH(4)-added Mg(NH(2))(2)-2LiH system. This finding provides us with a deep insight into the role played by NaBH(4) in the Li-Mg-N-H system, as well as ideas for designing high-performance catalysts for metal-N-H-based hydrogen storage media.
Liang
Chu
C
State Key Laboratory of Silicon Materials & Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
Liu
Yongfeng
Y
Jiang
Ying
Y
Wei
Zhijun
Z
Gao
Mingxia
M
Pan
Hongge
H
Wang
Qidong
Q