摘要
La-Mg-Ni系储氢合金因放电容量高、能量密度大和倍率性能好而成为最有前途的镍氢电池负极材料之一。然而,La-Mg-Ni系储氢合金存在制备困难、循环稳定性较差的缺点,严重阻碍其实际应用。如何优化制备工艺、提高循环稳定性,对于La-Mg-Ni系储氢合金是要解决的首要问题,相关研究具有重要的学术价值。一般来说,La-Mg-Ni系储氢合金主要包括AB_(3)、A_(2)B_(7)以及A_(5)B_(19)型三种晶体结构。三种晶体结构均是由一个AB_(2)型结构单元和一个或多个AB_(5)型结构单元沿c轴叠加而成。实际制备的La-Mg-Ni系储氢合金通常含有多相结构,其性能与合金的结构密切相关,而合金的结构又与合金的制备工艺密切相关。采用常规熔炼法制备La-Mg-Ni系储氢合金时,由于Mg的熔点和沸点均低于其他合金成分,在熔炼过程中的高温状态下Mg极易挥发。此外,Mg的挥发导致反应难以控制,使得合金成分不准确,严重影响合金的性能。为此,研究者们尝试采用先进的方法来制备La-Mg-Ni系储氢合金,如球磨、快速凝固、高压烧结、共沉淀-还原扩散法等,同时也尝试将多种方法联合使用来制备La-Mg-Ni系储氢合金,并探究了制备工艺对La-Mg-Ni系储氢合金相结构和电化学性能的影响。近年来,联合采用两种或两种以上工艺制备La-Mg-Ni系储氢合金的研究居多。研究表明,多种制备方法联合使用能够显著改变合金的电化学性能,特别是退火处理对储氢合金的循环稳定性起到有效的改善作用。本文首先介绍了La-Mg-Ni系储氢合金中超晶格合金相的结构。随后重点关注了近年来国内外对于La-Mg-Ni系储氢合金所采用的不同制备技术,包括熔炼法、机械合金化、烧结法、快淬法以及材料的后续处理等,并探讨了不同制备技术制得的合金的微观结构和电化学性能。同时,对各种制备方法进行综合评述,为如何制备出性能优良的La-Mg-Ni系储氢合金提供思路和依据。最后,对La-Mg-Ni系储氢合金的未来发展趋势进行了分析与展望。
La-Mg-Ni system hydrogen storage alloy is considered to be one of the most promising anode materials for nickel-hydrogen battery due to its high discharge capacity,high energy density and good rate performance.However,the La-Mg-Ni system hydrogen storage alloy has the disadvantages of difficult preparation and poor cycle stability,which seriously hinder its practical application.Therefore,how to optimize the preparation process and improve the cycle stability of the La-Mg-Ni system hydrogen storage alloy is the primary problem to be solved.The related research has important academic value.Generally speaking,La-Mg-Ni system hydrogen storage alloys mainly include three crystal structures,AB_(3)-type,A_(2)B_(7)-type and A_(5)B_(19)-type.Each of the three crystal structures is stacked with one AB_(2)unit and one or more AB_(5)units along the c axis.The actually prepared La-Mg-Ni system hydrogen storage alloy usually contains a multi-phase structure,and its performance is closely related to the structure of the alloy,while the structure of the alloy is closely related to the preparation process of the alloy.When the La-Mg-Ni system hydrogen storage alloy is prepared by the conventional smelting method,since the melting point and the boiling point of Mg are much lower than that of other alloy components,Mg is very easy to volatilize at high temperature during the smelting process.In addition,the volatilization of Mg makes it difficult to control the reaction,and the alloy composition is inaccurate,which seriously affects the performance of the alloy.Therefore,researchers have tried preparing La-Mg-Ni system hydrogen storage alloys by advanced preparation methods such as ball milling,melt spinning,high pressure sintering,co-precipitation-reduction diffusion method,etc.At the same time,researchers have also tried combining a variety of methods to prepare La-Mg-Ni system hydrogen storage alloys.The influence of the preparation process on the alloy phase structure and its electrochemical performance has also been studied.In recent years,there have been most studies on the combination of two or more preparation processes to prepare La-Mg-Ni system hydrogen storage alloys.It is found that the combination of multiple preparation methods can also significantly improve the electrochemical properties of the La-Mg-Ni system hydrogen storage alloy,especially annealing treatment effectively improving the cycle stability of the La-Mg-Ni system hydrogen storage alloy.The superlattice phase structure in the La-Mg-Ni system hydrogen storage alloy is firstly introduced in this paper.Then,different preparation processes of La-Mg-Ni system hydrogen storage alloys at home and abroad in recent years are focused,including melting,mechanical alloying,sintering,melt-spinning and subsequent treatment of materials.The microstructure and the electrochemical performance of the alloys prepared by different preparation techniques are explored.At the same time,various preparation methods are comprehensively reviewed,providing ideas and basis for the research on how to prepare La-Mg-Ni system hydrogen storage alloys with excellent properties.Finally,the future development trend of La-Mg-Ni system hydrogen storage alloys is analyzed and prospected.
作者
纪铭悦
田晓
刘昕瑀
田璐
杨艳春
塔娜
JI Mingyue;TIAN Xiao;LIU Xinyu;TIAN Lu;YANG Yanchun;TA Na(School of Physics and Electronic Information,Inner Mongolia Normal University,Hohhot 010022,China;Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials,Inner Mongolia Normal University,Hohhot 010022,China;Inner Mongolia Engineering and Research Center for Rare Earth Functional and New Energy Storage Materials,Inner Mongolia Normal University,Hohhot 010022,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第15期87-96,共10页
Materials Reports
基金
内蒙古自治区科技计划项目(2019GG264)
内蒙古师范大学研究生科研创新基金项目(CXJJS20097)
内蒙古师范大学大学生创新训练项目(XCY-2001)
国家自然科学基金(21865021)。
关键词
La-Mg-Ni系储氢合金
制备方法
相结构
电化学性能
La-Mg-Ni system hydrogen storage alloy
preparation process
phase structure
electrochemical property
