Zr-Ti系贮氢合金表面改性研究

New Surface Modification of Zr-Ti Hydrogen Storage Alloys

摘要:

采用化学镀镍、镀钴、机械混合以及球磨几种方法对Zr-Ti系贮氢合金进行了表面改性。XRD结果表明，随着镀镍量的增加，合金越趋向微晶化；球磨时间越长，合金的衍射峰更加弥散化，充放电试验结果表明，当镀镍量为15％(质量分数，下同)时，贮氢合金在60mA.g^-1的电流密度下初始容量比未处理的合金高出130mAh．g^-1，经过6次～8次循环完全活化，最大放电容量可达400mAh．g^-1，随着镀镍量的增加，抗自放电能力增加；当镀钴量为5％时，贮氢合金在60mA．g^-1的电流密度下初始容量比未处理的合金高出40mAh．g^-1，经过7次～9次循环完全活化，最大放电容量可达390mAh．g^-1，但随着镀钴量的增加，初始容量上升较快，但放电容量在减少；而机械混合仅提高初始容量，对最大放电容量没有改善；球磨不仅改善贮氢合金的活化性能，并且其最大放电容量可达450mAh．g^-1。

Abstract:

The surfaces of Zr-Ti hydrogen storage alloys are modified with methods such as chemical plating of nickel or cobalt, mechanical mixture, ball grinding and so on. XRD shows that the alloy has the trend to form micro-crystals with the content of coating nickel increasing, and long grinding time leads to dispersion of diffraction peaks of alloys. When the discharge current density is 60mA.g-1, the initial capacity of the alloy electrode plated Ni 15wt% is 130 mAh.g-1 more than that of untreated alloy. The alloy is activated absolutely after 6 cycles ~8 cycles, and the max discharge capacity can reach 400 mAh.g-1. The discharge capacity of alloy electrode with 5% Co can be up to 390 mAh.g-1. Anti-discharge ability increases with the percentage of Ni plated. The activation behavior of hydrogen storage alloys is also improved by ball grinding, and the max discharge capacity can reach 450 mAh.g-1. Mechanical mixture can only increase initial capacity without any improvement of max discharge capacity.