镁基储氢材料的性能及研究进展

Properties and research progress of magnesium based hydrogen storage materials

镁基储氢材料具有储氢容量高、价格低廉、在自然界中镁资源丰富等优点,被认为是最具有发展前景的一类固态储氢材料。由于MgH_(2)稳定性好且放氢焓值高(75kJ/mol H_(2)),氢分子在Mg表面解离能高及氢原子在镁晶格中扩散速率慢,导致吸放氢热力学稳定、动力学缓慢,从而限制了其在储氢方面的应用。对于镁基储氢材料性能的改善,目前已经取得了许多研究成果。本文综述了国内外镁基储氢材料的研究报道,归纳了镁基储氢材料的改性方法,重点阐述了合金化、纳米化和添加催化剂对于优化和改善热力学和动力学性能以及吸放氢机理的影响。最后对该领域的研究成果和发展前景进行了总结和展望,基于现有分析认为,在未来的研究中可以综合运用添加催化剂和纳米化改性双重机制对MgH_(2)体系热力学性能进行调控,以获得具有高容量、高性能的Mg/MgH_(2)储氢体系,满足商业化应用的要求。

Magnesium based hydrogen storage materials have the advantages of high hydrogen storage capacity,low price,and abundant magnesium resources in nature,and thus are considered as the most promising solid hydrogen storage materials.Due to the good stability of MgH_(2),the high enthalpy of hydrogen desorption(75kJ/mol H_(2)),the high dissociation energy of hydrogen molecules on the surface of Mg and the slow diffusion rate of hydrogen atoms in the magnesium lattice,the absorption and desorption of hydrogen are stable in thermodynamics but the kinetics is slow,which limits its application in hydrogen storage.Many research achievements have been made to improve the properties of magnesium based hydrogen storage materials and this paper reviews these research reports,and summarizes the modification methods with the focuses on the effects of alloying,nanocrystallization and catalyst addition on the optimization and improvement of the thermodynamic and kinetic properties,and the mechanism of hydrogen absorption and desorption.Finally,the development prospects in this field are prospected.Based on the existing analysis,it is concluded that catalyst addition and nano modification should be comprehensively used to regulate the thermodynamic properties of MgH_(2)system in the future research obtain the Mg/MgH_(2)hydrogen storage system with high capacity and high performance,which could meet the requirements of commercial applications.