摘要
为了降低AB_5型储氢合金的成本,对低钴的Ml_(0.9)Mg_(0.1)Ni_(3.4)Co_(0.3)Al_(0.3)合金的组织结构和性能进行了研究,并与工业储氢合金MmNi_(3.55)Co_(0.75)Mn_(0.4)Al_(0.3)进行了对比。实验结果表明：此低钴合金是由LaNis主相和LaNi_3第二相构成。它们的储氢量(ω,％)分别为1.36％和1.37％,最大放电容量分别为320 mAh／g和324 mAh／g,循环稳定性为：300次充放电循环后,2种合金剩余容量都是88％。但Ml_(0.9)Mg_(0.1)Ni_(3.4)Co_(0.3)Al_(0.3)的高倍率放电性能明显优于MmaNi_(3.55)Co_(0.75)Mn_(o.4)Al_(0.3)合金。主要原因是由于LaNi_3第二相的生成不仅提高了合金颗粒表面的电化学催化活性,而且提高了结构韧性从而抵消了低钴合金颗粒粉化的不利影响。
For decreasing the cost of ABs-type hydrogen storage alloys, a low-cobalt Ml0.9Mg0.1Ni3.4Co0.3Al0.3 alloy was investigated by examining the alloy structure, phase composition and some properties. Its properties were compared with those of a commercial alloy MmNi3.55Co0.75Mn0.4Al0.3. The experiments＇ outcome shows that the low-cobalt alloy is composed of Mg-free LaNi5 phase as matrix and Mg-contained LaNi3 phase as secondary phase. The hydrogen storage capacity （1.36wt% and 1.37wt% respectively）, the greatest discharge capacity （320 mAh/g and 324 mAh/g respectively） and cycling stability （the residual capacity of two alloys is all 88%） of Ml0.9Mg0.1Ni3.4Co0.3Al0.3 are as good as those of MmNi3.55Co0.7sMn0.4Al0.3. However, after the discharge current density exceeds 300 mA/g, the high-rate discharge abilities （HRD） of Ml0.9Mg0.1Ni3.4Co0.3Al0.3 are apparently better than those of MmNi3.55Co0.75Mn0.4Al0.3.It is because there exists Mg-contained LaNi3 phase as secondary phase which improves the electrochemical catalytic activity of alloy particles surface and the structure toughness of alloy particles.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2005年第12期1866-1870,共5页
Rare Metal Materials and Engineering
基金
国家教育部科技重点项目(104266)
关键词
储氢材料
低钴储氢合金
非化学计量比
电化学性能
PCT曲线
hydrogen storage materials
low-cobalt hydrogen storage alloy
non-stoichiometric
electrochemical property
PCT curve
