【作者】 盛丹；

【导师】 闫慧忠；

【作者基本信息】 内蒙古大学 ， 无机化学， 2009， 硕士

【摘要】 本文在绪论中综述了储氢合金的应用原理、研究发展与现状等,以储氢量较高的AB_3.0-3.5（新型RE-Mg-Ni系）储氢合金作为研究对象,较为系统地研究了A/B比和退火热处理对材料的结构特征、电化学性能以及自放电性能的影响。通过中频感应熔炼制备了La_0.65Mg_0.35Ni_x（x=3.0-3.5）系列储氢电极合金。研究了合金的结构、电化学性能以及自放电性能。XRD研究表明,该系列合金主要由三相组成:LaNi₅相、（La,Mg）Ni₃相和（La,Mg）₂Ni₄相,随着x值的增大,LaNi₅相的丰度逐渐增加,（La,Mg）Ni₃相的丰度逐渐减少;最大放电容量从350.6mAh·g^-1（x=3.0）增加到351.2mAh·g_-1（x=3.1）,然后逐渐减小到244.1mAh·g^-1（x=3.5）;合金电极72h的荷电保持率从77.7%（x=3.0）增加到79.5%（x=3.1）然后逐渐减小到63.5%（x=3.5）。x=3.1的合金的荷电保持率最高,表明AB_3-3.5型La-Mg-Ni系储氢合金的A/B比对合金电极的自放电性能有较大的影响。另一方面,研究了1173K热处理对该系储氢合金结构和性能的影响,并且对该系列合金电极的热处理前后进行对比。结果表明,热处理后的合金电极最大放电容量、循环稳定性、高倍率放电性能（HRD）、电极的自放电都有明显改善。更多还原

【Abstract】 The application status,research and development of hydrogen storage alloy were comprehensively introduced in the first part of this paper.The new series of RE-Mg-Ni based AB_3.0-3.5-type alloys with PuNi₃-type structure had higher capacity than that of the AB₅-type alloys and thus were regarded as promising candidates for reversible hydrogen storage.In this work,the effect of the A/B ratio and annealing treatment on the structural,electrochemical properties and self-discharge property of the AB_3.0-3.5-type hydrogen storage alloys has been studied systematically.The La_0.65Mg_0.35Ni_x（X=3.0-3.5） hydrogen storage alloys is prepared by induction melting.The structure,electrochemical properties and self-discharge property of as-cast alloys have been studied systematically by X-ray diffraction（XRD）,scanning electron microscope（SEM） and electrochemical experiments.It is found by XRD analysis that all these alloys mainly consist of three phases:the LaNi₅ phase, （La,Mg）Ni₃ phase and（La,Mg）₂Ni₄ phase.The abundance of the LaNi₅ phase increases and that of La（La,Mg）Ni₃ phase decreases with increasing x.The electrochemical studies show that as x increases the maximum discharge capacity of the alloy electrodes first increases from 350.6mAh·g^-1（x=3.0）to 351.2mAh·g^-1（x=3.1）and then decreases to 244.1mAh·g^-1（x=3.5）.Moreover,the capacity retention rate of 72h self-discharge increases from 77.7%（x=3.0）to 79.5%（x=3.1）,and then decreases to 63.5%（x=3.5）.When x=3.1,the capacity retention rate of alloy electrode is the maximum.Besides,lectrochemical experiments show that the discharge capacity,high rate discharge performance,cycle stability and self-discharge property of the La_0.35Mg_0.65Ni_x（X=3.0-3.5） alloy electrodes were improved after annealing treatment at 1173K.更多还原