论文部分内容阅读
采用机械合金化方法制备MmNi3.9Co0.45Mn0.4Al0.25-CoB复合储氢合金。通过X射线衍射(XRD)分析、扫描电子显微镜(SEM)分析、充放电及线性极化测试,研究了球磨时间对复合储氢合金相结构及电化学性能的影响。研究结果表明:随着球磨时间的增加,复合储氢合金的衍射峰逐渐宽化,杂散衍射峰消失,表现出非晶化趋势;复合储氢合金颗粒尺寸变小,并呈球状均匀分布。电化学测试结果表明:当球磨时间达到45min时,复合储氢合金具有较好的活化及高倍率放电性能,30次循环容量保持率最高,达到90.66%,表现出良好的电化学动力学性能及催化活性。但当球磨时间过长时,合金颗粒出现相互粘连及团聚的情况,局部出现较大结块,导致复合合金电极的交换电流密度降低。
Preparation of MmNi3.9Co0.45Mn0.4Al0.25-CoB composite hydrogen storage alloy by mechanical alloying. The effect of milling time on the phase structure and electrochemical performance of the composite hydrogen storage alloy was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), charge-discharge and linear polarization tests. The results show that the diffraction peak of the composite hydrogen storage alloy is broadened and the stray diffraction peak disappears with the increase of the milling time, showing the tendency of amorphization. The size of the composite hydrogen storage alloy becomes smaller and uniformly distributed in a spherical shape. The results of electrochemical tests show that the composite hydrogen storage alloy has good activation and high rate discharge performance when ball milling time reaches 45min, and the capacity retention rate of 30 cycles reaches the highest, reaching 90.66%, showing good electrochemical and kinetic properties Catalytic activity. However, when the ball milling time is too long, the alloy particles appear conglutination and agglomeration, and the larger agglomeration occurs locally, resulting in the decrease of the exchange current density of the composite alloy electrode.