第30卷第10期 2015年10月
文章编号：1000-324X(2015)10-1049-07
无机材料学报
Journal of Inorganic Materials
Vol. 30 No. 10 Oct.,2015
DOI:10.15541/jim20150125
稀土系A2B型La1-rScNi2.6Co0.3Mno.5Alo.1(x=0~0.5）
储氢合金相结构和电化学性能研究梅兴志"，罗永春1,2，张国庆"，康龙1
(兰州理工大学1.材料科学与工程学院；2.有色金属先进加工与再利用省部共建国家重点实验室，兰州730050) 摘要：真空电弧熔炼制备了AzB型La1-,Sc,Ni2.6Coo.3Mno.5Alo.1(x=0~0.5)储氢合金并进行退火热处理。XRD及 SEM/EDS分析结果表明，合金退火组织由LazNiz、LaNis、LaNi和ScNiz等相组成。合金生成恰计算表明，Sc-Ni 体系的生成恰比La-Ni和Mg-Ni体系的生成恰更负，这是含Sc合金易于形成ScNiz相以及成相规律有别于含 Mg合金的主要原因之一。合金电极最大放电容量和循环寿命Sioe随着Sc含量x增加均呈先增大后减小规律，当 x=0.2时，合金电极具有最大的放电容量(267.1mAh/g)和较好的容量保持率Sioo(80.47%)。掺入适量Sc元素后可抑制AzB型合金的氢致非晶化，但掺入Sc后合金易形成难吸氢的ScNiz相，这是合金电极容量不高的主要原因。关键词：稀土-镍系A,B，型储氢合金；元素替代；相结构；电化学性能
中图分类号：TG146
文献标识码：A
Structural andElectrochemicalProperties ofA,B--typ
La1-rScrNi2.6Coo.3Mno.5Alo.1 (x = 0~0.5) Hydrogen Storage Alloys MEI Xing-Zhi', LUO Yong-Chun' 2, ZHANG Guo-Qing', KANG Long
(1. Department of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China; 2. State Key Laboratory of Advanced Processing and Recyeling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China)
Abstract: A,B-type Lal-Sc,Niz.Coo.:Mne.sAle.(x = 00.5) hydrogen storage alloys were prepared by vacuum arc melting method and annealed at 1173 K. XRD and SEM-EDS results showed that the annealed alloys mainly consisted of La,Ni, LaNis, LaNi, and ScNiz phases. The enthalpy of formation calculation analyses showed that the enthalpy of formation of binary alloy of Sc-Ni was more negative than that of La-Ni and Mg-Ni. This was one of the main reasons that the phase rule of Sc-contained alloy was different from Mg-contained alloy, which facilitated forming ScNiz phase. The electrochemical measurement results showed that the discharge capacity and the cycle stability of the alloys were all firstly increased and then decreased with the x value increasing. The discharge capacity and cyclic stability (Sroe) of alloy electrodes reached the maximum of 261.1 mAh/g and 80.47%, respectively, when x value was equal to 0.2. The appropriate amount of Sc in alloy could obviously in-hibit the hydrogen-induced amorphous, meanwhile the alloy with Sc content also tends to form the non-hydrogen absorbing ScNi2 phase, which is the main reason that the discharge capacity of alloy electrode is not significantly improved.
收稿日期：2015-03-16；收到修改稿日期：2015-05-25
基金项目：国家高技术研究发展计划(863计划)(2011AA03A408)
National High-Tech Research and Development Program of China (863 Program) (2011AA03A408)
作者简介：梅兴志(1988)，男，硕士研究生.E-mail:m520zxm@163.com 通讯作者：罗永春，教授.E-mail:luoyc@lut.cn