Effect of stoichiometric ratio on discharge efficiency of hydrogen storage alloy electrodes
Effect of stoichiometric ratio on discharge efficiency of hydrogen storage alloy electrodes
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DOI：
10.1016/s0925-8388(97)00040-6
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发表时间：
1997-08
影响因子：
6.2
通讯作者：
C. Iwakura;Masayoshi Miyamoto;H. Inoue;M. Matsuoka;Y. Fukumoto
中科院分区：
文献类型：
--
作者：
C. Iwakura;Masayoshi Miyamoto;H. Inoue;M. Matsuoka;Y. Fukumoto
对非化学计量比和化学计量比Mm（B5）（B5= Ni 3.6Mn 0.4Al 0.3Co 0.7，x = 0.88，0.96，1.00，1.12）合金的放电效率进行了评价。放电效率随氢在合金中扩散激活能的增加而降低。X射线衍射分析表明，Mm（B5）0.88合金中出现了Ce 2Ni 7型第二相，形成了非常稳定的氢化物; Mm（B5）1.12合金中出现了Ni 3Al型第二相，具有很高的催化活性。具有较大x值或较高电催化活性的Mm（B5）合金具有较高的放电效率。因此认为，不仅氢在合金中的扩散，而且在合金/溶液界面处的电荷转移是负责放电效率的提高。
Discharge efficiencies were evaluated for nonstoichiometric and stoichiometric Mm(B5), (B5= Ni3.6Mn0.4Al0.3Co0.7, x = 0.88, 0.96, 1.00, 1.12) alloys. The discharge efficiency decreased with an increase in activation energy for hydrogen diffusion in the alloys. X-ray diffraction data showed the appearance of Ce2Ni7-type second phase, which formed a very stable hydride, for the Mm(B5)0.88alloy and Ni3Al-type one, which had high catalytic activity, for the Mm(B5)1.12alloy, respectively. The Mm(B5), alloys with larger x values or higher electrocatalytic activity showed higher discharge efficiency. It was therefore considered that not only hydrogen diffusion in the alloys but also charge transfer at the alloy/solution interface are responsible for the improvement of the discharge efficiency.