镧镍系合金对氢化镁组织结构与储氢性能的影响及机理  

Effect and Mechanism of LanthanumNickel Series Alloy on the Microstructures and Hydrogen Storage Performance of Magnesium Hydride

作　　者：刘宇[1] 张健[1] 庞小通 周小杰 卢先正 陈小敏 李佳豪 彭平[2] LIU Yu;ZHANG Jian;PANG Xiaotong;ZHOU Xiaojie;LU Xianzheng;CHEN Xiaomin;LI Jiahao;PENG Ping(College of Mechanical and Vehicle Engineering,Changsha University of Science and Technology,Changsha 410114,China;College of Materials Science and Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]长沙理工大学机械与运载工程学院,长沙410114 [2]湖南大学材料科学与工程学院,长沙410082

出　　处：《材料导报》2025年第8期134-139,共6页Materials Reports

基　　金：国家自然科学基金(51874049);湖南省研究生科研创新项目(LXBZZ2024208);长沙理工大学专业学位研究生实践创新与创业能力提升计划项目(CLSJCX23047)。

摘　　要：采用真空熔炼法制备出La_(m)Ni_(n)合金,进而将其与MgH_(2)按照不同比例高能球磨,获得MgH_(2)-x%La_(m)Ni_(n)(x=5,10,15)储氢复合体系,并结合实验表征与第一性原理计算,系统研究了La_(m)Ni_(n)添加对MgH_(2)组织结构与储氢性能的影响及机理。结果表明,La_(m)Ni_(n)合金主要由LaNi5主相以及少量的LaNi_(3)、La_(2)Ni_(3)相组成,其添加对MgH_(2)吸放氢具有明显的催化作用。复合体系中MgH_(2)-10%La_(m)Ni_(n)储氢性能最为优异,其在247℃下即可开始放氢,该体系在300℃、500 s内可释放6.0%(质量分数)的氢气,在300℃、120 s内其吸氢量可达理论储氢量的84%。吸放氢过程中,MgH_(2)与La_(m)Ni_(n)原位反应生成Mg_(2)Ni与LaH_(3),原位生成的Mg_(2)Ni、LaH_(3)以及原有的LaNi_(5)对MgH_(2)吸氢均表现出催化作用,有效促进了H2解离,提高体系的吸氢动力学;而放氢时,LaH_(3)则为主要催化相,其与MgH_(2)之间产生电荷转移,有效削弱了Mg-H键强,进而改善其放氢动力学。The La_(m)Ni_(n) alloy was prepared by vacuum melting method,and then it was milled with MgH_(2) according to different ratios by using high energy ball milling to obtain MgH_(2)-xwt%La_(m)Ni_(n)(x=5,10,15)hydrogen storage composite systems.Combined with experimental characterization and firstprinciple calculations,the effect and mechanism of La_(m)Ni_(n) addition on the microstructures and hydrogen storage properties of MgH_(2) were studied systematically.The results show that La_(m)Ni_(n) alloy is mainly composed of LaNi_(5) phase and a small amount of LaNi_(3) and La_(2)Ni_(3) phases,and the addition of La_(m)Ni_(n) alloy shows an obvious catalytic effect on hydrogen absorption and desorption of MgH_(2).Among these MgH_(2)-xwt%La_(m)Ni_(n)(x=5,10,15)composite systems,the MgH_(2)-10wt%La_(m)Ni_(n) has the best hydrogen storage performance,It can start hydrogen desorption at 247℃,and can release 6.0% hydrogen at 300℃ within 500 s,and has a hydrogen absorption capacity of 84% of the theoretical hydrogen storage capacity at 300℃ within 120 s.In the process of hydrogen absorption and desorption,Mg_(2) Ni and LaH_(3) are generated by the in situ reaction of MgH_(2) with La_(m)Ni_(n),Mg_(2) Ni and LaH_(3) and primitive LaNi5 all catalyze the hydrogen absorption of MgH_(2),which effectively promotes the dissociation of H_(2),thus improves the hydrogen absorption kinetics of the system.During hydrogen desorption,LaH_(3) is the main catalytic phase,and the charge transfer between LaH_(3) and MgH_(2) occurs,which effectively weakens the bonding strength of Mg-H and improves the hydrogen desorption kinetics.

关 键 词：氢化镁 催化掺杂 镧镍系合金 吸放氢动力学 第一性原理计算 

分 类 号：TG139.7[一般工业技术—材料科学与工程]