A、B侧元素化学计量比对La-Mg-Ni-Co系四元储氢合金的电化学性能影响研究  

Effect of Stoichiometric Ratio of A, B-Side on Electrochemical Performance of La-Mg-Ni-Co-Based Quaternary Hydrogen Storage Alloys

作　　者：李振轩[1] 朱文[1] 谭聪[1] 崇保和[1] 杨学兵[1] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,湖北武汉430074

出　　处：《稀有金属材料与工程》2015年第2期397-402,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助(21173090);深圳市战略性新兴产业发展专项资金(JCYJ20120618100557119)

摘　　要：采用共沉淀-还原扩散法制备了具有不同化学计量比的La-Mg-Ni-Co系储氢合金(AB3、AB3.3、AB3.5),重点考察B侧元素不同化学计量比对四元合金La-Mg-(Ni-Co)x(x=3.0,3.3,3.5)相结构和电化学性能的影响规律。结果表明,成分合金La0.67Mg0.33Ni2.5Co0.5(x=3.0)具有良好的综合电化学性能。同时采用3种电化学动力学实验分别对合金电极表面的电荷转移阻抗和电荷转移速率以及合金体相中氢的扩散速率进行了表征。证实合金元素化学计量是通过影响合金电极表面的电荷转移和合金体相中氢的扩散速率综合作用来改变其电化学动力学性能。La-Mg-Ni-Co-based hydrogen storage alloys with various stoichiometric ratios were prepared using a coprecipitation-reductiondiffusion method. The effects of stoichiometric ratios of B-side position on phase structure and electrochemical properties were investigated. The results show that La0.67Mg0.33Ni2.5Co0.5（x=3.0） alloy exhibits the best overall electrochemical performances among the sample investigated. Three electrochemical kinetic experiments were performed to characterize the hydrogen diffusion rate in the bulk alloy, and the charge transfer resistance and rate on the alloy electrode surfaces. It is confirmed that the stoichiometric ratio of alloy can influence the charge transfer on the alloy electrode surfaces as well as the hydrogen diffusion rate in the bulk alloy with a combined effect to alter the electrochemical kinetics.

关 键 词：共沉淀还原扩散法 La-Mg-Ni-Co 储氢合金 相结构 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程]