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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 kinetic properties of Mg1-xNdxNi0.5 (x = 0,0.05,0.1,0.15,0.2) hydrogen storage alloys were studied. Electrochemical tests show that the alloy reaches the maximum discharge capacity after 1 to 2 cycles and has good activation performance. The substitution of Mg for Nd can improve the cycling stability of the as-cast alloy and improve the discharge capacity of the alloy significantly. The XRD results show that the phase transition from single phase to multi-phase is possible due to the addition of Nd. However, excessive Nd can lead to the decrease of corrosion resistance and the decrease of electrochemical capacity retention rate. The kinetic tests show that the high-rate discharge (HRD) property of the alloy first increases and then decreases with the increase of Nd content, The results agree well with the results of hydrogen diffusion coefficient, indicating that suitable amount of Nd substitution obviously increases the high rate discharge capability of alloy and effectively improves the hydrogen storage kinetics of Mg2Ni alloy. When x = 0.15, the alloy not only has a higher discharge capacity but also shows good kinetic properties.