镨部分替代镧对Mm-Mg-Ni合金电化学性能影响的研究  

Effect of Partial Substitution of Praseodymium for Lanthanum on Electrochemical Performance of Mm-Mg-Ni Alloy

作　　者：卿培林 韦宁燕[2] 蓝志强[2] 张浩[2] 郭进[2] Qing Peilin;Wei Ningyan;Lan Zhiqiang;Zhang Hao;Guo Jin(Department of MaterialsScience and Engineering, Baise College, Baise 533000, China;Guangxi Key Laboratory of Processingfor Non-ferrous Metal and Featured Materials, College of Physical Science and Technology,Guangxi University, Nanning 530004 , China)

机构地区：[1]百色学院材料科学与工程学院,广西百色533000 [2]广西大学物理科学与技术学院广西有色金属及特色材料加工重点实验室物理科学与工程技术学院,广西南宁530004

出　　处：《中国稀土学报》2019年第3期344-350,I0004,共8页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(51571065);广西自然科学基金项目(2017GXNSFAA198337,2018GXNSFAA294125);2019年广西壮族自治区硕士学位授予单位立项建设项目(30401190);广西本科高校特色专业及实验实训教学基地(中心)建设项目(970104005)资助

摘　　要：通过感应熔炼制备Mm0.75Mg0.25Ni3.5Co0.2Al0.3(以下简称Mm-Mg-Ni)合金,研究Pr部分替代La对Mm-Mg-Ni合金电化学性能的影响,研究发现合金主要由MmNi5, LaAlNi4及La2Ni7组成。随着Pr含量增加,合金主相MmNi5的晶胞体积从0.08821 nm^3(x=0)减小至0.08768 nm^3(x=20),得益于晶胞体积收缩,合金电极充放电循环稳定性增强,经过100次充放电循环后,合金电极的电化学容量保持率由66.4%(x=0)逐渐增加至66.4%(x=5), 70.9%(x=10), 73.6%(x=15)及73.7%(x=20)。此外,以Pr部分替代La,还能提高合金电极的电化学动力学性能。在放电电流密度为1200 mA·g^-1时,合金电极的高倍率放电性能HRD1200从56.3%(x=0)分别增加到57.1%(x=5), 57.5%(x=10), 76.3%(x=15)及77.1%(x=20)。The Mm0.75Mg0.25Ni3.5Co0.2Al0.3(marked as Mm-Mg-Ni) alloy was prepared by induction melting, and the electrochemical properties of Mm0.75Mg0.25Ni3.5Co0.2Al0.3 alloy were studied by replacing La with Pr. It was found that the alloys mainly contained MmNi5, LaAlNi4 and La2Ni7 phase. The cell volume of the MmNi5 decreased from 0.08821 nm^3(x=0) to 0.08768 nm^3(x=20) as increasing Pr content, which was beneficial to suppress the pulverization of the alloy electrode during the charge and discharge process, thereby facilitating the improvement of the charge-discharge cycle stability of the electrode. After 100 times of charge-discharge cycles, the electrochemical capacity retention of the alloy electrode was increased from 66.4%(x=0) to 66.4%(x=5), 70.9%(x=10), 73.6%(x=15) and 73.7%(x=20), respectively. In addition, the results also showed that replacing the partial La with Pr can improve the electrochemical kinetics of the alloy electrode. The high-rate discharge performance of the alloy electrode at the discharge current density of 1200 mA·g^-1 was 56.3%(x=0) increased to 57.1%(x=5), 57.5%(x=10), 76.3%(x=15) and 77.1%(x=20), respectively.

关 键 词：储氢合金 储氢性能 电化学性能 循环稳定性 稀土 

分 类 号：TG139[一般工业技术—材料科学与工程]