纯La及混合稀土镁基储氢合金的性能研究

Investigation on Electrochemical Properties of Pure La and Ml Mg-Based Hydrogen-Storage Electrode Alloys

摘要:

用共沉淀还原扩散法制备了不同化学计量比的LaMg2Ni9-xCox（x=0．3-6．0）和M／Mg2Ni9-xCox（x=0．3-4．5）稀土镁基储氢电极合金。电化学测试结果表明：制得的合金活化性能良好；在Co含量x逐渐增大的过程中，合金的活化次数没有发生明显的变化，合金的放电容量逐渐减小，合金的循环稳定性逐渐增强。混合稀土合金比纯镧合金的活化次数多、放电量小，但是循环稳定性好。合金结构分析表明，合金主相为MgNi2相和LaNi5相，随着Co含量增加，LaCo5相和LaCo3相含量增加。

Abstract:

Rare-earth Mg-based hydrogen storage electrode alloys of LaMg2Ni9-xCox(x=0.3~6.0) and MlMg2Ni9-xCox(x=0.3~4.5) with different stoichiometric ratios were prepared by coprecipitation-reduction-diffusion method. Electrochemical analyses showed that the alloys prepared by this method can be easily activated; with x increasing, no obvious change for the activity numbers, and the discharge capacity decreased and the cyclic stability of alloy electrodes was effectively improved. Their activity numbers were larger than La-alloys, the discharge capacity decreased and the cyclic stability of mix-alloys was better than La-alloys. Structure analyses showed that the main phases of alloys were MgNi2 and LaNi5, the amount of LaCo5 phase and LaCo3 phase increased with Co content increasing.