烧结工艺对La_(1.6)Mg_(0.4)Ni_(7)合金相结构和电化学性能的影响  

Effects of powder sinteringmethod on the structure and electrochemical properties of La_(1.6)Mg_(0.4)Ni_(7) hydrogen alloys

作　　者：黄文杰 朱辉 丁荣 常毅 徐荣明 魏范松[1] HUANG Wenjie;ZHU Hui;DING Rong;CHANG Yi;XU Rongming;WEI Fansong(Department of Materials Scienceand Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,Jiangsu,China)

机构地区：[1]江苏科技大学材料科学与工程学院,江苏镇江212003

出　　处：《金属功能材料》2022年第5期44-48,共5页Metallic Functional Materials

基　　金：国家自然科学青年基金资助项目(50901036);江苏省研究生科研实践计划资助项目(SJCX20_1460)。

摘　　要：粉末烧结制备了La_(1.6)Mg_(0.4)Ni_(7)合金,系统研究了不同烧结工艺对合金相结构和电化学性能的影响。结果表明,合金主要由LaNi_(5)、La_(1.6)Mg_(0.4)Ni_(7)和LaNi_(5)相组成,其中La_(2)Ni_(7)相丰度随烧结时间的增加而增加,LaNi_(5)则与之相反。合金电极具有较好的循环性能(S_(100)≥78%)和高倍率性能(HRD_(900)≥83%),但最大放电容量较低,约150 mAh/g,活化性能较差。研究认为,活化性能降低与LaNi_(5)相的减少相关;吸氢相晶胞体积的增大,降低了合金颗粒的吸放氢体积膨胀率,这是合金循环性能较好的主要原因;合金电极的高倍率性能主要受合金表面电化学反应速率的影响。The La_(1.6)Mg_(0.4)Ni_(7)alloys were prepared by powder sintering, and the effects of different sintering methods on the phase structure and electrochemical properties of the alloys were systematically studied. The results reveal that all the alloys are composed of LaNi_(5), La_(1.6)Mg_(0.4)Ni_(7)and LaNi_(5)phases. As the sintering periods growing, the phase abundance of La_(2)Ni_(7)increases while it′s contrary to LaNi_(5)phase. The alloy electrodes present good cyclability(S_(100)≥78%) and high-rate discharge ability(HRD_(900)≥83%) but low maximum discharge capacity about 150 mAh/g, and the activation properties become worse with the sintering periods growing. It is found that the activation properties worsen because of decline of phase abundance of LaNi_(5), and the main reason for good cyclability is that the increase of cell volume of hydrogen absorption reduces the volume expansion rate of particles of alloys during ab-desorbing process, and the high-rate discharge ability is depended on electrochemical reaction rate on the surface of the alloys.

关 键 词：储氢合金 粉末烧结 LA-MG-NI系 

分 类 号：TG139.7[一般工业技术—材料科学与工程]