Hydrogen storage properties of the CeH_2 doped Li-Mg-N-H/NaAlH_4 system

The mutual destabilization between complex hydrides and lithium amide has been comprehensively reported. In this paper, CeH2 doped Li-Mg-N-H/NaAlH4 composite was successfully synthesized by ball milling Li-Mg-N-H mixture and NaAlH4 in a molar ratio of 1：2. It was found that a total of 5 wt.% of hydr...

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Bibliographic Details
Published inJournal of rare earths Vol. 29; no. 6; pp. 599 - 603
Main Author 张旭刚 李志念 王树茂 米菁 蒋利军 吕芳 刘晓鹏
Format Journal Article
LanguageEnglish
Published Elsevier B.V 2011
Subjects
ball milling
Li-Mg-N-H
NaAlH 4
NaAlH4
rare earths
reversibility
XRD分析
一步反应
储氢性能
原始材料
复合材料
温度范围
系统
reversibility
ball milling
NaAlH 4
Li-Mg-N-H
rare earths
Online AccessGet full text
ISSN1002-0721
2509-4963
DOI10.1016/S1002-0721(10)60505-4

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Summary:The mutual destabilization between complex hydrides and lithium amide has been comprehensively reported. In this paper, CeH2 doped Li-Mg-N-H/NaAlH4 composite was successfully synthesized by ball milling Li-Mg-N-H mixture and NaAlH4 in a molar ratio of 1：2. It was found that a total of 5 wt.% of hydrogen could be desorbed from the newly synthesized composite with a three-step reaction. Temperature-programmed-desorption （TPD） measurements showed that the composite ball milled for 10 min began to desorb hydrogen below 100 °C, which was about 75 °C lower than the pristine materials. XRD analysis revealed that NaAlH4 firstly reacted with LiH to yield Na2LiAlH6 and Al below 150 °C, then the newly developed Na2LiAlH6 reacted with Mg（NH2）2 to form NaH, Al, and Li2MgN2H2 in the temperature range of 180–250 °C. From 200 to 300 °C, the newly formed Al and Li2MgN2H2 reacted further to form Li2NH and some stable phase （AlN and Mg3N2）. The H-cycling properties of the composite were further investigated by a standard Sievert’s type apparatus at 150, 200 and 250 °C, respectively. Finally, the reversibility of the newly synthesized composite was discussed.
Bibliography:The mutual destabilization between complex hydrides and lithium amide has been comprehensively reported. In this paper, CeH2 doped Li-Mg-N-H/NaAlH4 composite was successfully synthesized by ball milling Li-Mg-N-H mixture and NaAlH4 in a molar ratio of 1：2. It was found that a total of 5 wt.% of hydrogen could be desorbed from the newly synthesized composite with a three-step reaction. Temperature-programmed-desorption （TPD） measurements showed that the composite ball milled for 10 min began to desorb hydrogen below 100 °C, which was about 75 °C lower than the pristine materials. XRD analysis revealed that NaAlH4 firstly reacted with LiH to yield Na2LiAlH6 and Al below 150 °C, then the newly developed Na2LiAlH6 reacted with Mg（NH2）2 to form NaH, Al, and Li2MgN2H2 in the temperature range of 180–250 °C. From 200 to 300 °C, the newly formed Al and Li2MgN2H2 reacted further to form Li2NH and some stable phase （AlN and Mg3N2）. The H-cycling properties of the composite were further investigated by a standard Sievert’s type apparatus at 150, 200 and 250 °C, respectively. Finally, the reversibility of the newly synthesized composite was discussed.
11-2788/TF
Li-Mg-N-H; NaAlH4; ball milling; reversibility; rare earths
ZHANG Xugang , LI Zhinian , WANG Shumao , MI Jing , JIANG Lijun, Lü Fang , LIU Xiaopeng （Department of Energy Materials and Technology, General Research Institute for Non-Ferrous Metals, Beijing 100088, China）
ISSN:1002-0721
2509-4963
DOI:10.1016/S1002-0721(10)60505-4