A study on structure and electrochemical properties of (La, Ce, Pr, Nd)2MgNi9 hydrogen storage electrode alloys
A study on structure and electrochemical properties of (La, Ce, Pr, Nd)2MgNi9 hydrogen storage electrode alloys
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DOI：
10.1016/j.electacta.2006.03.083
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发表时间：
2006-10
影响因子：
6.6
通讯作者：
Faliang Zhang;Yong-chun Luo;A. Deng;Zhaohui Tang;L. Kang;Jianhong Chen
中科院分区：
文献类型：
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作者：
Faliang Zhang;Yong-chun Luo;A. Deng;Zhaohui Tang;L. Kang;Jianhong Chen
通过感应熔炼和长时间退火处理制备了(La,Ce,Pr,Nd)2MgNi9储氢合金。通过正交设计实验研究了退火合金的结构和电化学性能。系统地研究了每种替代元素的单独作用及其在合金中的相互作用。研究表明，合金主相结构属于PuNi3型，空间群为R-3m。稀土元素的替代对合金的相结构和显微组织都有显着的影响。合金晶体结构的各向异性变化会引起合金颗粒粉化加速，导致合金电极循环稳定性变差。混合稀土可以提高氢吸收/解吸的平台压力。合金的放电容量范围为342.97至380.68mAhg−1，具体取决于替代元素的种类和含量。铈和钕都会明显降低合金电极的放电容量。与La2MgNi9合金电极相比，混合金属可以显着提高合金电极的高倍率放电性能。合金电极动力学特性的改善主要源于合金块体中氢扩散速率的增加。
(La, Ce, Pr, Nd)2MgNi9hydrogen storage alloys were prepared through induction melting followed by a long annealing treatment. The structure and electrochemical properties of annealed alloys have been investigated by orthogonal design experiments. Both the individual effects of each substituting element and their interaction in alloys were studied systemically. It has been shown that the structure of main phase in alloys belongs to PuNi3-type with a space group R-3m. Substituting rare-earth elements have a significant effect on both the phase structure of alloys and microstructure. The anisotropic change in the crystal structure of alloys can cause the acceleration of pulverization of alloy particles and result in the deterioration of the cyclic stability of alloy electrodes. Misch metals can raise the plateau pressure of hydrogen absorption/desorption. The discharge capacity of alloy ranges from 342.97 to 380.68mAhg−1depending on the sort and content of substituting elements. Both cerium and neodymium can obviously reduce the discharge capacity of alloy electrodes. When compared to the La2MgNi9alloy electrode, mish metals can significantly improve the high rate dischargeability of alloy electrodes. The improvement of the kinetic characteristic of alloy electrodes mainly results from the increase of the hydrogen diffusion rate in alloy bulk.