球磨Mg22Y2Ni10Cu2+x%Ni复合材料储氢性能研究

Hydrogen Storage Properties of Mg22Y2Ni10Cu2+ x% Ni Composite Prepared by Ball Milling

采用不同球磨时间（10，20，30，40h）制备了Mgz2Y2Ni10Cu2＋x％Ni（x=0，50，100，150；质量分数）复合材料，并对材料的结构、形貌、电化学及动力学储氢性能进行了系统的研究。分析了球磨时间和镍添加量对Mg22Y：Ni10Cu2合金储氢性能的影响。结果表明，球磨可以改善合金的显微结构，促进合金中非晶、纳米晶的形成，而镍的加入显著促进了该过程的进行，使复合材料中非晶、纳米晶的含量大幅度升高；随球磨时间和镍复合量的增加，合金放电比容量显著增加，当复合镍为x=100、球磨时间为40h时，其值已达到最大的669．7mAh·g^-1。循环稳定性的改善也较为明显，复合镍x=150、球磨20h试样的s20已经达到了80％。此外，球磨和镍的添加还可以明显优化合金的高倍率放电、交流阻抗和动电位极化等动力学性能。此外，包覆于合金表面的镍不但对合金性能起到催化作用，提高了合金的表面活性，还有效地提高了合金的综合储氢性能。

Mg22Y2Ni10Cu2 ＋ x% Ni （x = 0, 50,100, 150; mass fraction） composite were prepared by ball milling with different length of time （10, 20, 30, 40 h）. To elucidate the effect of the milling time and the addition of Ni on the hydrogen storage property of Mg22Y2Ni10Cu2, the structures, morphology, electrochemical and dynamic of hydrogen properties of the alloy were investigated sys- tematically. The results suggested that the microstrueture was improved and the.formation of amorphous and nanoctystalline was promo- ted due to the milling process, and meanwhile the addition of Ni could enhance the process of the formation of amorphous and nanoerys- talline. With the increasing of the milling time and the amount of Ni addition, the maximum discharge capacity and cycle stability were improved, i.e. the capacity reached its maximum value of 669.7 mAh-g-I as the Ni addition was x = 100 and milling time was 40 h. The improvement of cycle stability was obvious, i.e. the capacity was found to reach 80% in the condition of composite Ni with x = 150 and 20 h of milling. The addition of Ni optimized the dynamic performance of the alloy, e.g. the high rate discharge property （ HRD）, electrochemical impedance spectrum and the potentiodynamic polarization, etc. In addition, by coating the surface of the alloy, Ni cat- alyze and improve the surface activity, thereby promotes the hydrogen storage property of Mg22Y2Nil0Cu2.