Re₂Mg(Ni_{0.7 − x}Co_0.2Mn_0.1Al_x)₉ (x = 0‒0.04) alloys are prepared by induction melting, and the influence of the partial substitution of Ni by Al on the structure, hydrogen storage, and electrochemical properties of the alloys are investigated systematically. These alloys mainly consist of two main phases with LaNi₅ phase and (La,Mg)₂Ni₇ phase, and minor LaNi₂ phase. The pressure-composition isotherms shows that, with Al content increasing in the alloys, the maximum hydrogen storage capacity decreased from 1.16 wt% (x = 0) to 0.99 wt% (x = 0.04). The changes of enthalpy and entropy reveal that the thermodynamic stability and the disordered degree of the hydride alloys increase with the Al addition. Results of electrochemical studies indicate that the substitution of Al for Ni can noticeably improve the cycle stability of the alloy electrode. The capacity retention after 80 cycles is enhanced from 63.6% (x = 0) to 76.5% (x = 0.04). However, the maximum discharge capacity of the alloys decreases. The Re₂Mg(Ni_{0.7 − x}Co_0.2Mn_0.1Al_x)₉ (x = 0‒0.04) alloys exhibit excellent dischargeability.

中文翻译：

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AB 3型Re 2 Mg（Ni 0.7-x Co 0.2 Mn 0.1 Al x）9（x = 0‒0.04）合金的结构和储氢性能

通过感应熔炼制备了Re ₂ Mg（Ni _{0.7-  x} Co _0.2 Mn _0.1 Al _x）₉（x  = 0‒0.04）合金，以及Al部分取代Ni对组织，储氢和电化学的影响系统地研究了合金的性能。这些合金主要由LaNi ₅相和（La，Mg）₂ Ni ₇相两个主要相和次要的LaNi ₂相组成。压力组成等温线表明，随着合金中Al含量的增加，最大储氢量从1.16 wt％（x ＝ 0）至0.99wt％（x ＝ 0.04）。焓和熵的变化表明，氢化铝合金的热力学稳定性和无序度随着Al的添加而增加。电化学研究的结果表明，用Al代替Ni可以显着提高合金电极的循环稳定性。80个循环后的容量保留率从63.6％（x  = 0）提高到76.5％（x  = 0.04）。但是，合金的最大放电容量降低。Re ₂ Mg（Ni _{0.7-  x} Co _0.2 Mn _0.1 Al _x）₉（x = 0‒0.04）合金具有出色的放电性能。