轻金属合金薄膜储氢的理论研究

项目名称： 轻金属合金薄膜储氢的理论研究

项目编号： No.10874154

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 孙强

作者单位： 郑州大学

项目金额： 30万元

中文摘要： 轻金属合金是目前非常受重视的很有前途的储氢材料。但氢在轻金属表面的解离和扩散势垒较大，而且形成金属氢化物后脱附温度较高。 如何降低氢的解离势垒和脱附能一直是理论和实验上具有挑战性的课题。本项目提出一种区别于传统的全新的量子调制的方法应用于氢在轻金属薄膜中的储存和释放：利用金属超薄薄膜的量子限制效应来调控氢的解离和扩散势垒，改变氢在薄膜中的热力学性质，降低脱附能。利用密度泛函理论和热力学统计方法，对氢在不同厚度的轻金属及其合金薄膜表面的吸附、解离、扩散和复合以及氢扩散进入薄膜内部的原子过程进行研究，着重研究基于薄膜厚度及掺杂形成的电子密度变化对轻金属及其合金薄膜的稳定性，对氢在薄膜表面的吸附和扩散及所形成金属氢化物热力学性质的调制和影响。根据理论研究结果，以期能为在实际应用中得到理想的储氢合金薄膜材料提供理论依据。

中文关键词： 储氢材料；轻金属合金薄膜；量子尺寸效应；第一原理计算

英文摘要： Light metal alloys are one kind of promising materials for hydrogen storage. However, the barriers for hydrogen dissociation and diffusion at their surfaces as well as temperatures for hydrogen desorption from the formed metal hydrides are high. How to low the dissociation and diffusions barriers and desorption energy of hydrogen from the metal hydrides is a big challenge for scientists.In the project we propose a new quantum tuning approach for hydrogen storage:By quantum size effect of ultrathin metal films, the dissociation and diffusion barriers and thermal stability of hydrogen in metal films may be tuned and consequently desorption energy of hydrogen may be lowed. Using density functional theory and thermal statistical method, we study hydrogen adsorption,dissociation,dffusion and desorption processes by altering thickness of thin films, and focus our attentions on the stability of the films with different thickness of films and doping, which may change the electron density of states at surface. And consequently adsorption and diffusion of hydrogen at the surfaces can be tuned, and so do the thermal properties of the formed metal hydride. By our theoretical study, we expect to find some suitable light metal films for hydrogen storage.

英文关键词： Hydrogen storage materials;Light metal alloy film;Quantum size effect;First-principles calculations