AB2型La1-xMgxNi2．28(X=0．0-0．6)贮氢合金相结构和电化学性能的研究  

Structure and Electrochemical Properties of AB2-Type La1-xMgxNi2.28 （x =0.0 -0.6） Hydrogen Storage Alloys

作　　者：李学军[1] 崔舜[1] 周增林[1,2] 宋月清[1] 林晨光[1] 黄长庚 钱文连 

机构地区：[1]北京有色金属研究总院粉末冶金及特种材料研究所,北京100088 [2]厦门钨业股份有限公司海沧分公司,福建厦门361026

出　　处：《中国稀土学报》2009年第2期234-240,共7页Journal of the Chinese Society of Rare Earths

基　　金：北京有色金属研究总院-厦门钨业股份有限公司贮氢合金联合实验室资助项目(2006090909)

摘　　要：用冷坩埚磁悬浮熔炼方法制备La1-xMgxNi2.28(x=0.0～0.6)贮氢电极合金,采用FESEM,EDS,XRD,p-c-t测试及三电极电化学性能测试研究合金的相成分、相结构、p-c-t曲线和电化学性能。EDS结合XRD分析表明,LaNi2.28合金主相为四方结构的La7Ni16相;Mg替代量x为0.3时合金主相为MgSnCu4型的LaMgNi4相,还含有LaNi5和(La,Mg)Ni3相。p-c-t曲线显示,当Mg替代量x不超过0.2时,合金无放氢平台;x为0.3时合金出现明显平台;x为0.5时合金出现两个放氢平台,相应贮氢量达到1.24%(质量分数)。电化学性能测试表明,最大放电容量从100.2 mAh.g-1(x=0.0)增大到329.0 mAh.g-1(x=0.5),然后减小到207.8 mAh.g-1(x=0.6);活化性能改善;高倍率放电性能先降低后提高;循环稳定性S100从84.8%(x=0.0)提高到91.5%(x=0.2),然后降低到63.3%(x=0.5)。The La1 -xMgxNi2.28 （x = 0.0 - 0.6） hydro- gen storage electrode alloys were prepared by cold crucible levitation melting under argon gas atmosphere. The phase constituent, phase structure, p-c-t curves and electrochemical properties of these alloys were investigated by means of FESEM, EDS, XRD, p-c-t test and tri-electrode test system. EDS along with XRD analysis showed that main phase of LaNi2.28 alloy was tetragonal La7Ni16 phase. And La0.7Mg0.3Ni2.28 alloy consisted of MgSnCu4-type LaMgNi4 main-phase, LaNi5 phase and （La, Mg）Ni3 phase. The p-c isotherms exhibited that the alloys with x less than 0.2 had no hydrogen-desorption plateau, and La0.7 Mg0.3Ni2.28 alloy began to have plateau. La0.5Mg0.5Ni2.28 alloy even showed two plateaus with hydrogen storage capacity of 1.24% （ mass fraction）. The electrochemical results showed that the maximum discharge capacity （Cmax） increased from 100.2 mAh·g^-1 （x =0.0） to 329.0 mAh· g^- 1 （ x = 0.5 ）, and after that decreased to 207.8 mAh·g^-1 （x =0.6）. The activation property was also improved. The high-rate dischargeability first enhanced, and then reduced. The cyclic stability （S100） increased from 84.8% （x =0.0） to 91.5% （ x = 0.2）, then decreased to 63.3 % （x = 0.5 ）.

关 键 词：Mg AB2型 贮氢电极合金 相分析 P-C-T曲线 电化学性能 稀土 

分 类 号：TG139.7[一般工业技术—材料科学与工程]