A study on hydrogen storage and electrochemical properties of La_(0.55)Pr_(0.05)Nd_(0.15)Mg_(0.25)Ni_(3.5) (Co_(0.5)Al_(0.5))_x (x=0.0, 0.1, 0.3, 0.5) alloys  

作　　者：覃铭 蓝志强 丁杨 熊凯 刘奕新 郭进 

机构地区：[1]College of Physics Science and Technology,Guangxi University [2]Department of Physics and Electronic Engineering,Baise University

出　　处：《Journal of Rare Earths》2012年第3期222-227,共6页稀土学报（英文版）

基　　金：Project supported by National Natural Science Foundation of China (50861003, 51071054);the Natural Science Foundation of Guangxi (2010GXNSFD013004, 2011GXNSFA018034)

摘　　要：The La0.55Pr0.05Nd0.15Mg0.25Ni3.5（Co0.5Al0.5）x（x=0.0, 0.1, 0.3, 0.5） alloys were prepared by magnetic levitation melting under an Ar atmosphere, and the effects of Co and Al on the hydrogen storage and electrochemical properties were systematically investigated by pressure composition isotherms, cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy testing. The results showed that the alloy phases were mainly consisted of （La,Pr）（Ni,Co）5, LaMg2Ni9, （La,Nd）2Ni7 and LaNi3 phases, and the cell volumes of （La,Pr）（Ni,Co）5, LaMg2Ni9, （La,Nd）2Ni7 and LaNi3 phases expanded with Co and Al element added. The hydrogen storage capacity initially increased from 1.36 （x=0） to 1.47 wt.% （x=0.3） and then decreased to 1.22 wt.% （x=0.5）. The discharge capacity retention and cycle stability of the alloy electrodes were improved with the increase of Co and Al contents. The La0.55Pr0.05Nd0.15Mg0.25Ni3.5（Co0.5Al0.5）0.3 alloy electrode possessed better electrochemical kinetic characteristic.The La0.55Pr0.05Nd0.15Mg0.25Ni3.5（Co0.5Al0.5）x（x=0.0, 0.1, 0.3, 0.5） alloys were prepared by magnetic levitation melting under an Ar atmosphere, and the effects of Co and Al on the hydrogen storage and electrochemical properties were systematically investigated by pressure composition isotherms, cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy testing. The results showed that the alloy phases were mainly consisted of （La,Pr）（Ni,Co）5, LaMg2Ni9, （La,Nd）2Ni7 and LaNi3 phases, and the cell volumes of （La,Pr）（Ni,Co）5, LaMg2Ni9, （La,Nd）2Ni7 and LaNi3 phases expanded with Co and Al element added. The hydrogen storage capacity initially increased from 1.36 （x=0） to 1.47 wt.% （x=0.3） and then decreased to 1.22 wt.% （x=0.5）. The discharge capacity retention and cycle stability of the alloy electrodes were improved with the increase of Co and Al contents. The La0.55Pr0.05Nd0.15Mg0.25Ni3.5（Co0.5Al0.5）0.3 alloy electrode possessed better electrochemical kinetic characteristic.

关 键 词：hydrogen storage alloy hydrogen storage property electrochemistry property rare earths 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TM912[金属学及工艺—合金]