| Ti0.17Zr0.08V0.34Nb0.01Cr0.1Ni0.3氢化物电极合金微观结构及电化学性能研究 | |
| Microstructure and Electrochemical Characteristics of Ti0.17Zr0.08V0.34Nb0.01Cr0.1Ni0.3 Hydride Alloy | |
| 摘要: 采用XRD、FESEM-EDS、ICP及EIS等方法研究了Ti0.17Zr0.08V0.34Nb0.01Cr0.1Ni0.3氢化物电极合金微观结构和电化学性能。X射线衍射分析表明：该合金由体心立方结构(bcc)的V基固溶体主相和少量六方结构的C14型Laves相组成；FESEM及EDS分析表明：V基固溶体主相形成树枝晶，C14型Laves相呈网格状围绕着树枝晶的晶界，元素在两相中的分布呈现镜像关系。电化学性能测试结果表明：该合金的氢化物电极在303~343 K较宽的温度区间内，表现出较高的电化学容量，在303 K和343 K时，电化学容量分别为337.0 mAh·g-1和327.9 mAh·g-1。在303 K循环100周后，容量为282.7 mAh·g-1。ICP分析结果表明，氢化物电极在充放电循环过程中，V及Zr元素向KOH电解质中的溶出较为严重。EIS研究表明，金属氢化物电极表面电化学反应的电荷转移电阻(RT)随循环次数的增加而增加，相应的交换电流密度则随循环次数的增加而降低。氢化物电极循环过程中RT的增大以及V和Zr元素的溶解，可能是导致电极容量衰减的主要原因。 | |
| 关键词: Ni-MH电池 氢化物电极 V基固溶体 电化学阻抗 | |
| 基金项目: | |
| Abstract: Microstructure and electrochemical properties of Ti0.17Zr0.08V0.34Nb0.01Cr0.1Ni0.3 hydride alloy have been investigated by using XRD, SEM-EDS, ICP and EIS measurements. The result of XRD analysis shows that the alloy is mainly composed of V-based solid solution phase with body-centered-cubic (bcc) structure and C14 Laves phase with hexagonal structure. V-based solid solution phase is dendrite embeds mainly in the matrix of C14 Laves phase, and the distribution of the component elements in the two phases has a mirror relationship. The maximum discharge capacity of Ti0.17Zr0.08V0.34Nb0.01Cr0.1Ni0.3 hydride alloy has reached 337.0 mAh·g-1 with good cycle stability. The alloy electrode has a higher discharge capacity within a wide temperature region from 303 K to 343 K, and the discharge capacity is 327.9 mAh·g-1 at 343 K. ICP analyses indicate that the dissolution of V and Zr to KOH solution is rather seriously. The result of electrochemical impedance spectrometry (EIS) indicates that the charge transfer resistance (RT) increases with increasing cycle number and the exchange current density (I0) decreases with increasing cycle number. The increase of RT and the dissolution of V and Zr element are perhaps main factors affecting the discharge capacity. | |
| Keywords: Ni-MH battery metal hydride electrode V-based solid solution EIS | |
| 摘要点击次数: 1782 | |
| 全文下载次数: 1952 | |
| 乔玉卿,赵敏寿,李梅晔,朱新坚,曹广益.Ti0.17Zr0.08V0.34Nb0.01Cr0.1Ni0.3氢化物电极合金微观结构及电化学性能研究[J].无机化学学报,2006,22(3):415-420. | |
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