添加Ni对Mg—AI储氢合金电化学性能的影响

为探究添加Ni对Mg～A1储氢合金电化学性能的影响机制，笔者采用机械合金化在氩气保护下经高能球磨制备了添加5％Ni的MgssAl42储氢合金，利用电化学方法研究了球磨时间和添加Ni对其放电容量及腐蚀电化学性能的影响。结果表明：目前研究的储氢合金放电容量与球磨时间有关，随球磨时间的延长先变大，球磨10h时放电容量最大为408．5mAh·g^-1，此时的放电时间为490min，随后逐渐减少；储氢合金出现二次钝化现象，但二次钝化区间较短，腐蚀速度与球磨时间有关，球磨1h时腐蚀速度最低，此时的腐蚀电流密度为1．28×10^-5A·cm^-2;交流阻抗谱由单容抗弧组成，极化电阻随球磨时间的延长先减小再增大而后减小。添加5％Ni后合金放电容量最大，但腐蚀速度有所加快。

Effect of Ni addition on electrochemical properties of Mg-Al hydrogen storage alloy

In order to investigate the effect mechanisms of Ni addition on electrochemical properties of Mg-A1 hydrogen storage alloy, a Mgs8 A142 hydrogen storage alloy added by 5%Ni was prepared by mechanical alloying （MA） method and the effect of ball milling time and Ni addition on the discharge capacities and corrosion electrochemical properties was studied by means of electrochemical method. The results show that the discharge capacities of the present alloy increase and afterwards decrease with increment of ball milling time. The highest discharge capacity is 408. 5 Ah. g-1 and its discharge time is 490 rain when the alloy is milled for 10 h. There are passive phenomena in potentiodynamic polarization curves, but their ranges are very narrow. The corrosion rates of the present alloy increase at initial and decrease afterwards and finally increase again with the increment of ball milling time. The electrochemical impedance spectroscopies （EIS） are composed of single capacitive loop. Polarization resistances of the present alloy decrease at initial and afterwards increase and finally decrease again with the increment of ball milling time. The discharge capacities are highest when 5 %Ni is added to Mgs8 A142 alloy, but corrosion rates have a little increase.