摘要
采用机械合金化法制备了MlNi3.55Co0.75Mn0.4Al0.3+x%Mg(Ml=富镧混合稀土;x=3,5,7,10)复合储氢合金。利用X射线衍射和电化学测试方法对MlNi3.55Co0.75Mn0.4Al0.3铸态合金和MlNi3.55Co0.75Mn0.4Al0.3/Mg复合合金的相结构和电化学性能进行了研究。X射线衍射结果发现,MlNi3.55Co0.75Mn0.4Al0.3合金由单一的La Ni5相组成。而MlNi3.55Co0.75Mn0.4Al0.3/Mg复合合金由La Ni5主相和小量的(La,Mg)2Ni3相组成,且合金中(La,Mg)2Ni3相的含量随镁含量x的增大而增多。此外,当复合合金中镁含量较多(x=10)时,复合合金有非晶化的趋势。电化学性能测试结果发现,当添加镁含量较少(x≤7)时,合金的最大放电容量、放电性能以及循环稳定性都好于MlNi3.55Co0.75Mn0.4Al0.3合金的相应性能,其中x=5时,合金的综合电化学性能最佳。合金电化学性能的改善得益于合金中形成恰当比例的La Ni5和(La,Mg)2Ni3相。
MlNi3. 55Co0. 75Mn0. 4Al0. 3＋ x % Mg（Ml = La-rich misch metal; x = 3,5,7,10） composite hydrogen storage alloys were prepared by mechanical alloying method. The phase structures and electrochemical properties of the as-cast MlNi3. 55Co0. 75Mn0. 4Al0. 3alloy and the MlNi3. 55Co0. 75Mn0. 4Al0. 3/ Mg composite alloys have been investigated by means of X-ray diffraction（XRD） and electrochemical measurements. XRD results show that the as-cast MlNi3. 55Co0. 75Mn0. 4Al0. 3alloy consists of single La Ni5 phase. However,the MlNi3. 55Co0. 75Mn0. 4Al0. 3/ Mg composite alloys are composed of the La Ni5 phase and a small amount of the（La,Mg）2Ni3phase. And the content of（La,Mg）2Ni3in composite alloys increases with increasing x. Moreover,the introduction of more Mg promotes the formation of amorphous structure. Electrochemical studies show that the maximum discharge capacity,the discharge property and the capacity retention of composite alloy with x≤7 are better than that of the as-cast MlNi3. 55Co0. 75Mn0. 4Al0. 3alloy. And the composite alloy with x = 5 exhibits the best overall electrochemical properties. The improvements of the electrochemical properties of composite alloys are attributed to the proper ratio of La Ni5 phase to the（La,Mg）2Ni3phase in composite alloys.
出处
《稀土》
EI
CAS
CSCD
北大核心
2015年第1期69-73,共5页
Chinese Rare Earths
基金
内蒙古自然科学基金项目资助(2014MS0542)
内蒙古高等学校科学研究基金项目资助(NJZY11036)
内蒙古大学高层次人才基金项目资助(115304)
内蒙古师范大学研究生科研创新基金项目资助(CXJJSZD13006)
关键词
复合储氢合金
机械合金化
相结构
电化学性能
composite hydrogen storage alloy
mechanical alloying
phase structure
electrochemical properties
