高等学校化学学报

高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (8): 1929.doi: 10.7503/cjcu20130177

• 物理化学 • 上一篇    下一篇

Mg取代对LiBH4(010)面结构和储氢性能的影响

巩雪敬1, 成丽苹1, 许保恩1,2, 曾艳丽1, 李晓艳1, 孟令鹏1   

  1. 1. 河北师范大学化学与材料科学学院, 石家庄 050024;
    2. 石家庄学院化工学院, 石家庄 050035
  • 收稿日期:2013-02-27 出版日期:2013-08-10 发布日期:2013-07-19
  • 通讯作者: 孟令鹏,男,教授,博士生导师,主要从事量子化学计算和材料模拟与设计研究.E-mail:menglp@mail.hebtu.edu.cn E-mail:menglp@mail.hebtu.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 21171047, 21102033); 河北省自然科学基金(批准号: B2011205058)和河北省教育厅基金(批准号: ZD2010126, ZH2012106)资助.

Effects of Mg Substitution on Structure and Hydrogen Storage of LiBH4(010) Surface

GONG Xue-Jing1, CHENG Li-Ping1, XU Bao-En1,2, ZENG Yan-Li1, LI Xiao-Yan1, MENG Ling-Peng1   

  1. 1. College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China;
    2. College of Chemical Engineering, Shijiazhuang University, Shijiazhuang 050035, China
  • Received:2013-02-27 Online:2013-08-10 Published:2013-07-19

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摘要：

采用基于密度泛函理论的第一性原理, 研究了Mg取代Li原子对LiBH4(010)面的晶体结构、 H原子解离能及H原子迁移的影响. 结果发现, Mg取代后B-H键长增大, 更易于H原子的解离. 氢空位的出现也使其附近H原子的解离能减小. 电子结构计算结果表明, Mg取代Li原子后, 减弱了B-H之间的共价作用. 通过对氢原子在[BH4]单元之间扩散能垒的计算发现, Mg取代Li原子后, H原子的扩散能垒由4.84 eV降为3.01 eV, 表明H原子在体相内更容易迁移.

关键词: LiBH4, 储氢, 脱氢, 扩散, 第一性原理

Abstract:

The geometry, electronic structure, dehydrogenation energy and hydrogen atom migration on the clean and Mg doped LiBH4(010) surfaces were studied with first-principles calculations based on density functional theory(DFT). The lengths of B-H bond increase, and H atoms are easy to dissociate. Based on the H1 vacancy, we found that the presence of H vacancy is helpful to the formation of other kinds of H vacancy. Electronic structure reveals that the B-H bonds are weakened. By calculating the diffusion pathway of H atom from one [BH4] to the nearby [BH4] on the clean and Mg doped LiBH4(010) surfaces, we find that the migration barrier energy comes down from 4.03 eV to 3.09 eV. This indicates that the H atoms are easier to diffuse on the Mg doped LiBH4(010) surface.

Key words: LiBH4, Hydrogen storage, Dehydrogenation, Diffusion, First-principle calculation

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