真空电弧熔炼制备了 A2B7型 La1-xScxNi2.6Co0.3Mn0.5Al0.1(x=0~0.5)储氢合金并进行退火热处理。XRD 及SEM/EDS分析结果表明，合金退火组织由La2Ni7、LaNi5、LaNi和ScNi2等相组成。合金生成焓计算表明， Sc-Ni体系的生成焓比 La-Ni 和 Mg-Ni 体系的生成焓更负，这是含 Sc 合金易于形成 ScNi2相以及成相规律有别于含Mg合金的主要原因之一。合金电极最大放电容量和循环寿命S100随着Sc含量x增加均呈先增大后减小规律，当x=0.2时，合金电极具有最大的放电容量(267.1 mAh/g)和较好的容量保持率S100(80.47%)。掺入适量Sc元素后可抑制A2B7型合金的氢致非晶化，但掺入Sc后合金易形成难吸氢的ScNi2相，这是合金电极容量不高的主要原因。
A2B7-type La1-xScxNi2.6Co0.3Mn0.5Al0.1(x= 0–0.5) hydrogen storage alloys were prepared by vacuum arc melting method and annealed at 1173 K. XRD and SEM-EDS results showed that the annealed alloys mainly consisted of La2Ni7, LaNi5, LaNi, and ScNi2phases. The enthalpy of formation calculation analyses showed that the enthalpy of formation of binary alloy of Sc-Ni was more negative than that of La-Ni and Mg-Ni. This was one of the main reasons that the phase rule of Sc-contained alloy was different from Mg-contained alloy, which facilitated forming ScNi2phase. The electrochemical measurement results showed that the discharge capacity and the cycle stability of the alloys were all firstly increased and then decreased with thex value increasing. The discharge capacity and cyclic stability (S100) of alloy electrodes reached the maximum of 261.1 mAh/g and 80.47%, respectively, whenx value was equal to 0.2. The appropriate amount of Sc in alloy could obviously in-hibit the hydrogen-induced amorphous, meanwhile the alloy with Sc content also tends to form the non-hydrogen absorbing ScNi2 phase, which is the main reason that the discharge capacity of alloy electrode is not significantly improved.
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