| 热处理温度对La-Y-Ni合金相结构和电化学性能的影响 |
| Effect of Annealing Temperature on Structure and Electrochemical Properties of La-Y-Ni Alloy |
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| 摘要: 采用磁悬浮感应熔炼法制备了组分为LaY2Ni9.7Mn0.5Al0.3的合金，在不同温度（1 073~1 373 K）下对合金进行热处理，利用X射线衍射法（XRD）、电子探针（EPMA）和电化学性能测试等方法，系统地研究了热处理温度对合金相结构和电化学性能的影响。结果表明，热处理可以显著提高合金的相均匀度，随着热处理温度的升高合金中的主相Ce2Ni7相先增加后减少。电化学研究表明，合金电极的最大放电容量、倍率性能和循环稳定性随着热处理温度的升高均呈现先升高后降低的趋势，与Ce2Ni7相含量的变化一致。电化学压力-组成-温度（P-C-T）测试表明，合金具有2个放氢平台，且随着热处理温度的升高合金的放氢坪台压增加。当热处理温度为1 273 K时，合金的Ce2Ni7相含量最高为86.53%（w/w），电化学性能最佳，最大放电容量为386.80 mAh·g-1（60 mA·g-1），在电流密度为900 mA·g-1时的高倍率性能HRD900=89.45%，循环300周后的容量保持率S300=72.18%（300 mA·g-1）。 |
| 关键词: 镍氢电池 储氢合金 电化学性能 热处理 Ce2Ni7型相 坪台压 |
| 基金项目: 工信部工业转型升级强基工程（No.0714-EMTC02-5379/4）资助项目。 |
| Abstract: The LaY2Ni9.7Mn0.5Al0.3 alloy was prepared by magnetic suspension induction melting method. It was annealed at different temperatures from 1 073 to 1 373 K. The effect of annealing temperature on the phase structure and the electrochemical properties was systematically investigated by X-ray diffraction (XRD), electron probe micro analysis (EPMA), and electrochemical measurements. It was proved that the heat treatment significantly improved the phase uniformity of the alloy. The content of the main phase Ce2Ni7-phase increased first and then decreased with the annealing temperature. At the same time, the maximum discharge capacity, high rate discharge-ability and the cyclic stability of the alloy electrodes all increased first and then decreased, which were consistent with the change of the content of Ce2Ni7 phase. The electrochemical pressure-content-temperature (P-C-T) curves of the alloy electrodes had two hydrogen desorption platforms, and their pressures both increased with the annealing temperature. When the annealing temperature was 1 273 K, the Ce2Ni7 phase content of the alloy was 86.53%(w/w), and the electrochemical properties were the best. The maximum discharge capacity reached to 386.80 mAh·g-1 (60 mA·g-1), the high rate discharge-ability at current density of 900 mA·g-1 (HRD900) was 89.45%, and the maximum capacity retention after 300 cycles (S300) was 72.18% (300 mA·g-1). |
| Keywords: Ni-MH battery hydrogen storage alloy electrochemical properties heat treatment Ce2Ni7 type phase plateau pressure |
| 投稿时间：2019-01-14 修订日期：2019-04-08 |
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| 郭淼,苑慧萍,刘彧儒,蒋利军.热处理温度对La-Y-Ni合金相结构和电化学性能的影响[J].无机化学学报,2019,35(6):1041-1049. |
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