铸态和快淬态La-Mg-Ni储氢合金的电化学性能及其对BH_(4^(-))的催化氧化性能  

Electrochemical properties and catalytic oxidation properties for BH_(4^(-))of the as-cast and rapid quenched La-Mg-Ni hydrogen storage alloys

作　　者：纪铭悦 田晓[1,2,3] 刘昕瑀 张宇琦 伟伟[1] 杨艳春 JI Mingyue;TIAN Xiao;LIU Xinyu;ZHANG Yuqi;WEI Wei;YANG Yanchun(School of Physics and Electronic Information,Inner Mongolia Normal University,Hohhot 010022,Inner Mongolia,China;Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials,Inner Mongolia Normal University,Hohhot 010022,Inner Mongolia,China;Inner Mongolia Engineering and Research Center for Rare Earth Functional and New Energy Storage Materials,Inner Mongolia Normal University,Hohhot 010022,Inner Mongolia,China)

机构地区：[1]内蒙古师范大学物理与电子信息学院,内蒙古呼和浩特010022 [2]内蒙古师范大学功能材料物理与化学自治区重点实验室,内蒙古呼和浩特010022 [3]内蒙古师范大学稀土功能和新能源储能材料自治区工程研究中心,内蒙古呼和浩特010022

出　　处：《金属功能材料》2022年第4期56-63,共8页Metallic Functional Materials

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(CXJJS21129);内蒙古师范大学大学生创新训练项目(XCY-2130)。

摘　　要：采用熔炼法和熔炼+快淬法这两种制备方法分别制备了La_(0.625)Mg_(0.375)Ni_(2.485)Co_(0.525)Mn_(0.28)Al_(0.21)储氢合金。采用XRD、SEM/EDS和电化学测试分析方法研究了合金的结构、电化学性能以及对BH^(4)-的催化氧化性能。结果表明,铸态合金由大量的LaNi_(5)相,少量的La_(2)Ni_(7)和LaNi_(3)相组成。而铸态合金经快淬处理后,合金几乎全部由LaNi_(5)相组成。电化学测试表明,铸态合金经快淬处理后,合金的最大放电容量从288.04 mA·h/g下降到185.30 mA·h/g,但是合金的循环稳定性有明显的改善。经50次充放电循环后,容量保持率由铸态合金的92.85%上升到快淬态合金的97.44%,这主要与合金中富稀土La_(2)Ni_(7)和LaNi_(3)相的含量有关。在对BH_(4^(-))的催化性能研究中发现,铸态合金的氧化峰电流密度33.61 mA/cm^(2)明显高于快淬态合金的14.934 mA/cm^(2)。两种合金在电子转移数上相差不大。总体来看,铸态合金的电化学性能和对BH_(4^(-))的催化氧化性能都要好于快淬态合金的。La_(0.625)Mg_(0.375)Ni_(2.485)Co_(0.525)Mn_(0.28)Al_(0.21) hydrogen storage alloys were prepared by the melting method and the melting+rapid quenching method,respectively.The structure,electrochemical performance and catalytic performance for BH_(4)-of the alloy samples were analyzed by XRD,SEM/EDS and electrochemical analysis methods,respectively.The results showed that the as-cast La_(0.625)Mg_(0.375)Ni_(2.485)Co_(0.525)Mn_(0.28)Al_(0.21) alloy was composed of a large amount of LaNi_(5) phase and a small amount of La_(2)Ni_(7) and LaNi_(3) phases.However,the rapid quenched La_(0.625)Mg_(0.375)Ni_(2.485)Co_(0.525)Mn_(0.28)Al_(0.21) alloy was almost composed of LaNi_(5) phase.Electrochemical tests showed that the maximum discharge capacity of the as-cast alloy decreased from 288.04 mA·h/g to 185.30 mA·h/g after rapid quenching,but the cycling stability of the alloy improved significantly.After 50 charge-discharge cycles,the capacity retention rate of the as-cast alloy increased from 92.85% to 97.44% of that of the rapid quenched alloy,which was mainly related to the existence of rare earth-rich La_(2)Ni_(7) and LaNi_(3) phases in the alloy.In a study of the catalytic properties of BH_(4^(-)),it was found that the oxidation peak current density of the as-cast alloy,33.61 mA/cm^(2),was significantly higher than that of the rapid quenched alloy,14.934 mA/cm^(2).The difference in electron transfer numbers between the two alloys was not significant.Overall,the electrochemical performance and catalytic oxidation performance of as-cast alloys was better than those of rapid quenched alloy.

关 键 词：La-Mg-Ni储氢合金 快淬 电化学性能 催化性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程]