少量Si对无钴AB_5型储氢合金性能的影响

Research on Properties of Co-Free AB_5-Type Hydrogen Storage Alloys by Addition of a Little Si

采用电弧熔炼制备了La(NiAlMn)5-xSix(0≤x≤0.35)合金。借助XRD,SEM等分析了La(NiAlMn)5-xSix储氢合金的晶体结构和相组成,并研究了合金的电化学性能。结果表明:当x≤0.3时合金由LaNi5单相组成;当x=0.35时合金由主相LaNi5和第二相LaNi3构成。随着Si含量的增加,合金储氢量和放电容量减少。但是循环稳定性得到了改善。经300次充放电循环,合金在x=0.35时的容量损失率为19.4%。这是因为Si的加入使得合金的抗氧化性,耐腐蚀性得到了改善。

La（NiAlMn）5-xSix （0≤x≤0.35） alloys were prepared by inductive melting. The crystal structure of alloys was determined by X-ray and SEM, and the electrochemical properties were also investigated .The results show that the alloys are composed of LaNi5 as main phase, while x≤ 0.3.When x=0.35, the alloy is composed of LaNi5 as matrix and LaNi3 as secondary phase. With the increase of Si content the maximum discharge capacity and the high rate discharge （HRD） ability decrease gradually, however the cycle stability is improved correspondingly. The lowest capacity decay can remain 19.4 % （x=0.35） after 300 charge/discharge cycles. The lower corrosion current densities of the Si-containing alloys can be explanation for the good cycle life of them.