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采用X射线衍射方法、压力-成分等温线、电化学放电循环研究了AB5型La0.7Mg0.3Al0.3Mn0.4Co0.5-xSnxNi3.8(x=0,0.1,0.2,0.3,0.5)合金中用Sn替换Co对其显微结构、储氢性能和电化学放电容量的影响。XRD、SEM及EDS测试结果表明,所有的合金都主要由La Ni5和Mg Ni2相组成,但随着合金中Sn含量的逐渐增加,出现LaNiSn相且显微结构得到细化。压力-成分等温线表明,随着合金中Sn含量的增加,合金的最大储氢容量从1.48%(x=0)降低到0.85%(x=0.5)。电化学测试结果表明,随着合金中Sn含量的增加,合金的最大放电容量从337.1 mA·h/g(x=0)降低到249.8 mA·h/g(x=0.5);充放电循环100次的放电容量保持率从70.2%(x=0)增加到78.0%(x=0.5)。
X-ray diffraction method, pressure-component isotherm, electrochemical discharge cycle study AB5-type La0.7Mg0.3Al0.3Mn0.4Co0.5-xSnxNi3.8 (x = 0,0.1,0.2,0.3,0.5) alloy Effect of Co on the Microstructure, Hydrogen Storage and Electrochemical Discharge Capacity of Sn with Sn. The results of XRD, SEM and EDS show that all the alloys consist mainly of LaNi5 and MgNi2 phases. However, with the increase of Sn content in the alloy, LaNiSn phase appears and the microstructure is refined. The pressure-component isotherms show that the maximum hydrogen storage capacity decreases from 1.48% (x = 0) to 0.85% (x = 0.5) as the Sn content in the alloy increases. The results of electrochemical tests showed that the maximum discharge capacity decreased from 337.1 mA · h / g (x = 0) to 249.8 mA · h / g (x = 0.5) as the Sn content in the alloy increased. The secondary discharge capacity retention increased from 70.2% (x = 0) to 78.0% (x = 0.5).