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采用真空感应熔炼方法制备了La0.83Mg0.17Ni3.1Co0.3Al0.1和La0.63Gd0.2Mg0.17Ni3.2-xCo0.3Alx(x=0~0.4)贮氢合金,并在氩气气氛900℃进行退火处理。通过X射线衍射(XRD)、显微电子探针(EPMA)分析方法和电化学测试分析研究了Gd和Al元素对合金微观组织和电化学性能的影响。研究结果表明,该系列合金退火组织主要由Ce2Ni7/Gd2Co7型、Pr5Co19型、PuNi3型和CaCu5型相组成;Gd元素的加入使合金中CaCu5型相明显减少,Ce2Ni7型/Gd2Co7型相显著增加,x=0.1时其相丰度达到81.2%;随Al含量x不断增加,合金中CaCu5型相丰度逐渐增多,当x=0.1~0.2时,CaCu5型相丰度为4%~5%,x=0.4时,其相丰度达到66.65%。电化学测试分析表明,Gd和Al元素对合金电极活化性能影响不大,当x=0.1时,含Gd合金电极放电容量达到最大值391 mAh.g-1,随Al含量x进一步增加,合金电极放电容量降低。含Gd和加入适量的Al元素可使合金电极循环稳定性得到明显提高,当Al含量x=0.1,0.2时,经100次充放电循环后其电极容量保持率S100分别为93.7%和90.1%,其中La0.63Gd0.2Mg0.17Ni3.1Co0.3Al0.1合金具有最好的综合电化学性能。
La0.83Mg0.17Ni3.1Co0.3Al0.1 and La0.63Gd0.2Mg0.17Ni3.2-xCo0.3Alx (x = 0 ~ 0.4) hydrogen storage alloys were prepared by the vacuum induction melting method, and were hydrogenated at 900 ℃ Annealed. The effects of Gd and Al on the microstructure and electrochemical properties of the alloy were investigated by X-ray diffraction (XRD), microelectron probe (EPMA) analysis and electrochemical measurements. The results show that the annealed microstructure consists of Ce2Ni7 / Gd2Co7, Pr5Co19, PuNi3 and CaCu5 phases. The addition of Gd significantly reduces the CaCu5 phase and the Ce2Ni7 / Gd2Co7 phase, while the x = 0.1, the phase abundance reached 81.2%. With the increase of Al content x, the abundance of CaCu5 phase in the alloy gradually increased. When x = 0.1 ~ 0.2, the abundance of CaCu5 phase was 4% ~ 5% 0.4, the phase abundance reached 66.65%. Electrochemical tests showed that Gd and Al had little effect on the activation of the alloy electrode. When x = 0.1, the discharge capacity of Gd alloy electrode reached the maximum of 391 mAh.g-1. With the further increase of Al content x, Discharge capacity decreases. When the content of Al is 0.1, 0.2, the electrode retention capacity S100 is 93.7% and 90.1%, respectively, after 100 cycles of charging and discharging with the addition of Gd and the proper amount of Al. Among them, La0.63Gd0.2Mg0.17Ni3.1Co0.3Al0.1 alloy has the best comprehensive electrochemical performance.