Mg_(1-x)Nd_xNi_(0.5)(x=0,0.05,0.10,0.15,0.20)贮氢合金的电化学与动力学性能研究

Electrochemical and Dynamic Properties of Mg_(1-x)Nd_xNi_(0.5)(x=0,0.05,0.1,0.15,0.2) Hydrogen Storage Alloys

研究了Mg1-xNdxNi0.5(x=0,0.05,0.1,0.15,0.2)贮氢合金的电化学与动力学性能。电化学测试表明:合金均在1～2次循环后达到最大放电容量,具有良好的活化性能。Nd替代Mg可以改善铸态合金的循环稳定性,并显著提高合金的放电容量,经XRD测试表明,这可能是由于添加Nd后合金由单相结构转变为多相结构,相界面增多的原因。但过量的Nd会导致抗腐蚀性减弱从而降低电化学容量保持率;动力学测试表明:随着Nd含量的增加,合金的高倍率放电(HRD)性能先增大后减小,这与交流阻抗测试和氢扩散系数的结果吻合良好,说明适量Nd替代明显提高了合金的高倍率放电能力,有效改善了Mg2Ni型合金的贮氢动力学性能。当x=0.15时合金不仅具有较高的放电容量且显示了良好的动力学性能。

The electrochemical and dynamic properties of Mg1-xNdxNi0.5（x=0,0.05,0.1,0.15,0.2） hydrogen storage alloy were investigated.The electrochemical tests showed that the alloy could up to the maximum discharge capacity after 1~2 crystals,and it had good activation performance.The substitution of Nd for Mg improved the cycle stability of the as-cast alloys,and significantly enhanced its discharge capacity,for the alloy changed from a single-phase into the multiphase structure by the substitution of Nd,but excessive Nd would weaken the corrosion resistance of alloy and reduced capacity retention rate.The dynamic tests indicated that the high rate discharge performance of the alloy gradually increased and then decreased with the increasing volume of Nd substitution,and the HRD presented a good match to electrochemical impedance spectrum measurement and the hydrogen diffusion coefficient,and showing that Nd substitution clearly improved the high rate discharge capacity and effectively improved the hydrogen dynamics properties of alloy.When x=0.15,the alloy not only had higher discharge capacity but also showed good dynamic properties.