Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5148094 | International Journal of Hydrogen Energy | 2017 | 10 Pages |
Abstract
A nanometric phosphoric complex salt additive was synthesized by hydrothermal method. Its catalytic effect on the hydrogen storage properties of MgH2 was investigated. MgH2+20Â wt.% LiFePO4 obtained by ball-milling process had an ability of absorbing 2.03Â wt.% hydrogen at 423Â K in 21Â min, and only 0.98Â wt.% could be absorbed by MgH2 for the identical condition. 3.61Â wt.% hydrogen could be released by the composite at 623Â K in 21Â min, whereas only 2.23Â wt.% was desorbed by as-received MgH2. Doping by nanometric LiFePO4 expressively enhanced the hydrogenation/dehydrogenation properties of MgH2, and changed the rate-controlling steps from three-dimensional interfacial reaction to one-dimensional diffusion process. Meanwhile, the onset dehydrogenation temperature for MgH2+20Â wt.% LiFePO4 was 653Â K, which was found to be 60Â K lower than the as-received MgH2. In addition, the addition of LiFePO4 also lowered the activation energy (Ea) 31Â kJÂ molâ1. Based on XRD and XPS analysis, the in situ formed phases LiMgPO4 and Fe, which are produced by the reaction between MgH2 and LiFePO4, may be responsible for the remarkable improvement in hydrogen storage properties of MgH2.
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Authors
Ying Cheng, Wei Zhang, Jian Liu, Kai Cheng, Zhen Zhao,