新型镁基储氢合金的合成及电化学性能的研究

Preparation and Electrochemical Characteristics ofa New Type Mg-based Hydrogen Storage Alloys

用扩散法成功地合成了Ｍｇ１．５Ａｌ０．５－ｘＮｉＶｘ(ｘ＝０,０．１,０．２,０．３,０．４)系列合金．ＸＲＤ结构分析表明,合金中出现一个新的物相,其化学式为Ｍｇ３ＡｌＮｉ２,属立方晶系,Ｆｄ３ｍ空间群,新相具有很好的电化学性能．钒的添加使合金的容量进一步提高．未经任何预处理的Ｍｇ１．５Ａｌ０．３Ｖ０．２Ｎｉ合金的最大放电容量达到３３３ｍＡ·ｈ·ｇ－１(５０ ｍＡ·ｇ－１,－０．５Ｖ ｖｓ．Ｈｇ/ＨｇＯ)．Ａｌ对六方晶系Ｍｇ２Ｎｉ合金结构中Ｍｇ的部分取代对于延长合金的循环寿命有重要作用．

The Mg-based hydrogen storage alloys Mg1.5Al0.5-xNiVx(x= 0, 0. 1, 0. 2, 0.3,0.4) were successfully synthesized by means of a diffusion method (MD). The structure of these alloys were examined by X-ray diffraction. A new phase was found in the alloys. Its chemical formula is Mg3AlNi2. Further studies reveal that the new phase has excellent electrochemical properties. The discharge capacity of Mg1.5Al0.5-xNiVx alloys increases owing to V addition and reaches the highest capacity of 333 mA.h.g-1 (50 mA.g-1:, -0. 5 V vs. Hg/HgO) without any treatment. The improvement of cycle life was ascribed to the partial substitution of Al for Mg in the alloy.