摘要
研究了La0.55Pr0.05NdxMg0.4-xNi3.3Al0.1(x=0.10,0.15,0.20)储氢合金的电化学性能。随着合金中Nd/Mg比的增加,合金电极的放电平台逐渐降低,电极极化减小。x=0.15的合金具有较高的电化学容量(372mAh.g-1),而x=0.10的合金具有较好的倍率放电能力(HRD1800=73.1%)。合金电极的循环寿命随着Nd含量的增加而逐渐改善。合金电极的电化学阻抗谱(EIS)表明,随Nd含量减小,合金电极的电荷迁移电阻逐渐减小,动力学性能增强。线性极化测试表明,随着Nd/Mg比的减小,合金电极表面的电化学反应速率增加。通过合金电极阳极电流对时间响应的半对数曲线计算的氢扩散系数随着Nd/Mg比降低而增加,说明合金内部的氢扩散能力也提高。
In this paper, the electrochemical performances of La0.55Pr0.05NdxMg0.4-xNi3.3Al0.1（x=0.10,0.15,0.20） hydrogen storage alloys were studied. The results show that, with increasing ratio of Nd/Mg, the discharge overpotential of the alloy electrodes gradually decreases, the alloy electrode for x = 0.15 shows maximum discharge capacities （372 mAh· g - 1 ）, and the alloy electrode for x = 0.10 exhibits good high rate dischargeability （HRDISCO =73.1% ）. The charge/discharge cycling stability of the alloy electrodes is improved with increasing Nd amount. Meanwhile, the results of the electrochemical impedance spectroscopy, linear polarization, anode polarization, and hydrogen diffusion coefficient measurements all indicate that the exchange current density I0, the limiting eurrent density IL and the hydrogen diffusion coefficient D of the alloy electrodes also increase with increasing Nd content in alloys, which signifies that lower Nd/Mg ratio is favorable to improve the electrochemical kinetics property of the La0.55Pr0.05NdxMg0.4-xNi3.3Al0.1（x=0.10,0.15,0.20） hydrogen storage alloys.
出处
《稀土》
EI
CAS
CSCD
北大核心
2008年第2期1-6,共6页
Chinese Rare Earths
基金
国际科技合作项目(2006DFB52550)
国家自然科学基金项目资助(20363001)
