MH/Ni电池用铸态及快淬态RE−Mg−Ni−Co−Al基合金的电化学储氢性能

摘要

The La?Mg?Ni?Co?Al-based AB2-type La0.8?xCe0.2YxMgNi3.4Co0.4Al0.1 (x=0, 0.05, 0.1, 0.15, 0.2) alloys were prepared via melt spinning. The analyses of the X-ray diffraction (XRD) and scanning electron microscopy (SEM) proved that the experimental alloys contain the main phase LaMgNi4 and the second phase LaNi5. Increasing Y content and spinning rate lead to grain refinement and obvious change of the phase abundance without changing phase composition. Y substitution for La and melt spinning make the life-span of the alloys improved remarkably, which is attributed to the improvement of anti-oxidation, anti-pulverization and anti-corrosion abilities. In addition, the discharge capacity visibly decreases with increasing the Y content, while it firstly increases and then decreases with increasing spinning rate. The electrochemical kinetics increases to the optimum performance and then reduces with increasing spinning rate. Moreover, all the alloys achieve to the highest discharge capacities just at the initial cycle without activation.%采用快淬方式制备La?Mg?Ni?Co?Al基AB2型La0.8?xCe0.2YxMgNi3.4Co0.4Al0.1(x=0,0.05,0.1,0.15,0.2)合金.XRD、SEM分析表明,实验合金包含主相LaMgNi4和第二相LaNi5.增加Y含量和淬速导致晶粒细化及相丰度明显改变,但不改变相组成.元素Y替代La元素和快淬使合金寿命明显改善,这归因于抗氧化、抗粉化和抗腐蚀能力的改善.另外,放电容量随Y含量的增加明显减小,而随淬速的增加先增加后下降.电化学动力学随淬速的增加先增加到最佳性能然后再下降.所有合金在第一次循环过程中就达到最大放电容量,不需要活化过程.