Effects of spinning rate on structures and electrochemical hydrogen storage performances of RE-Mg-Ni-Mn-based AB_2-type alloys

快淬对RE-Mg-Ni-Mn系AB_2型贮氢合金结构及电化学性能的影响（英文）

La was partially substituted by Ce with the aim of improving the electrochemical hydrogen storage performances ofLa1–xCexMgNi3.5Mn0.5 (x=0, 0.1, 0.2, 0.3, 0.4) alloys, and melt spinning technology was adopted to fabricate the alloys. Theidentification of XRD and SEM reveals that the experimental alloys consist of a major phase LaMgNi4 and a secondary phase LaNi5.The growth of spinning rate results in that the lattice constants and cell volume increase and the grains are markedly refined. Theelectrochemical measurement shows that the as-cast and spun alloys can obtain the maximum discharge capacities just at the firstcycle without any activation needed. With the increase of spinning rate, the discharge capacities of the alloys first increase and thendecline, whereas their cycle stabilities always grow. Moreover, the electrochemical kinetic performances of the alloys first increaseand then decrease with spinning rate growing.

为了提高合金的电化学性能,采用Ce部分替代La,并结合快淬方法制备了La_(1–x)CexMgNi_(3.5)Mn_(0.5)(x=0,0.1,0.2,0.3,0.4)贮氢合金。XRD和SEM测试结果表明,合金由LaMgNi_4主相以及LaNi_5第二相组成。随着快淬速度的增加,合金的晶格参数及晶胞体积逐渐增大,晶粒明显得到细化。电化学测试结果表明,铸态及快淬态合金具有优异的活化性能,其放电容量均在第一次循环时即可达到最大值。随着快淬速度的增加,合金的放电容量先增大后减小,但其循环稳定性逐渐提高。此外,合金电极的电化学动力学性能均随快淬速度的增加先提高后降低。