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在全面评述稀土系AB_5型贮氢电极合金的研究进展基础上,对AB_5合金中A侧稀土组元作用机理和二侧元素计量比(A:B)对合金电化学性能影响规律分别进行了系统的研究。为设计和筛选高性能贮氢合金,首先对影响氢化物电极放电过程的因素进行理论和实验研究,设计了三种电化学测试系统并进行对比分析,建立了电化学容量评价方法。又根据氢化物电极的结构及放电过程,推导出多孔氢化物电极的极化方程,并进行实验验证。 作者对RE(NiCoMnTi)_5贮氢合金(RE=La_(1-x-x-y-z)Ce_xNd_yPr_z)中La,Ce,Nd和Pr含量及比例对其电化学性能的影响首次进行了系统的研究。为描述其综合效应,引入成分约束条件,作出综合电化学性能图,为筛选最佳的稀土成分提供依据。由于纯La,Ce,Nd和Pr价格昂贵,工业化生产中不宜直接采用纯稀土金属来配制电极合金。本研究进一步采用富镧混合稀土和富铈混合稀土按适当比例配制,以获得最佳合金成分,采用Rietveld方法对系列合金进行精细结构分析结果表明,合金仍保持母体合金LaNi_5的CaCu_5型六方晶系结构;合金中La,Ce,Nd,Pr(la)-Ni,Co,Mn,Ti(2c)键长对电化学容量起决定作用。 在优化A侧的基础上,进一步研究ABr合金中r值对电化学性能的影响,结果表明,超化学计量比(r=5.3)的合金具有较高的放电容量和较小的循
On the basis of reviewing the research progress of rare earth AB_5 type hydrogen storage electrode alloy, the influence mechanism of A side rare earth element in AB_5 alloy and the influence law of A / B ratio on the electrochemical performance of AB alloy are studied systematically Research. In order to design and select high-performance hydrogen storage alloy, the factors affecting the discharge process of hydride electrode were theoretically and experimentally studied. Three kinds of electrochemical test systems were designed and compared, and the electrochemical capacity evaluation method was established. According to the structure and discharge process of hydride electrode, the polarization equation of porous hydride electrode was deduced and verified by experiment. The effect of La, Ce, Nd and Pr contents on the electrochemical properties of RE (NiCoMnTi) _5 hydrogen storage alloys (RE = La_ (1-x_x_y_z) Ce_xNd_yPr_z) has been systematically studied for the first time. In order to describe its comprehensive effect, the introduction of composition constraints, to make a comprehensive electrochemical performance map, to provide the basis for screening the best composition of rare earth. Due to the high price of pure La, Ce, Nd and Pr, it is not advisable to use pure rare earth metals to prepare electrode alloys directly in industrialized production. In this study, we further prepared lanthanum-rich rare earth and cerium-rich mixed rare earth in proper proportions to obtain the best alloy composition. The Rietveld method was used to analyze the fine structure of the series alloys. The results showed that the alloy retained the CaCu_5-type hexagonal LaNi_5 Structure. The bond length of La, Ce, Nd, Pr (la) -Ni, Co, Mn and Ti (2c) in the alloy plays a decisive role in the electrochemical capacity. On the basis of optimizing the A side, the effect of r value on the electrochemical performance of ABr alloy was further studied. The results show that the alloy with high stoichiometry (r = 5.3) has higher discharge capacity and smaller cycle