掺杂元素Fe对LiAlH_4放氢性能影响的第一性原理研究  

First-principles Study of Dehydrogenation Characteristics of LiAlH_4 with Dopant Fe

作　　者：王青[1,2] 党文强[2] 杜瑞[2] 戴剑锋[1,2] 李维学[1,2] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050 [2]兰州理工大学理学院,甘肃兰州730050

出　　处：《计算物理》2012年第2期297-302,共6页Chinese Journal of Computational Physics

基　　金：国家自然科学基金(50873047);甘肃省教育厅(0903-12)资助项目

摘　　要：采用第一性原理赝势平面波方法研究掺杂元素Fe对LiAlH4放氢性能的影响及其作用机理.计算杂质形成能、电子态密度、氢原子分解能,分析原子间的成键情况和结构的稳定性.结果表明:Fe在LiAlH4中占据间隙位置或者替代Al或者Li时,都能改善LiAlH4的放氢性能.Fe在LiAlH4中倾向于占据间隙位置,电子结构分析显示Fe占据间隙位置时与近邻的Al原子产生强烈的相互作用;另一方面,Fe与近邻的H也有较强相互作用.两个因素共同的结果是破坏了[AlH4]基团的稳定性,从而改善LiAlH4的放氢性能.结果与实验相吻合.With plane-wave pseudo-potential method of first-principles,effect of dopant Fe on dehydrogenation characteristics of LiAlH4 and mechanism were studied.Dopant formation energy,electronic density of states and dissociation energy of H were investigated.Bonding state and structure-stability of the crystal were analyzed.It indicates that as Fe occupied an interstitial site,an Al site or an Li site,dehydrogenation properties of LiAlH4 were improved.Fe tended to occupy the interstitial site.Analysis on electronic structure reveals that there exist strong interactions between a dopant Fe and its nearest neighbouring Al atoms as Fe occupied an interstitial site.Meanwhile,interaction between a dopant Fe and its nearest neighbouring H atoms is also considerably strong.Stability of the ligand is distorted.Therefore,dehydrogenation properties of LiAlH4 are improved.In general,dopant Fe improve dehydrogenation properties of LiAlH4,which is consistent with experimental observations.

关 键 词：第一性原理 LiAlH4 FE 放氢性能 

分 类 号：O641[理学—物理化学]