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用固态扩散和机械球磨法制备出纳米级Mg2 Ni和Mg1 .7Al0 .3 Ni储氢合金 ,其电化学性能超过用传统方法制备的合金。充放电测试表明 :该合金放电电压平台 (电压超过 1 2V)较高 ;在 2 0 0mA/g放电电流密度下 ,合金充放电循环 50次 ,容量仍保持在 2 0 0mAh/g以上。X射线衍射分析表明 :随着球磨时间延长 ,衍射峰的宽化程度变大 ,强度逐渐减弱 ,1 2h后变化减缓。这是由于晶粒尺寸变小 ,缺陷及应力密度增加之故。合金电化学性质的改善与合金在机械研磨中的微结构变化有关 ,并且合金组成中铝部分取代镁对于延长合金的循环寿命有至关重要的作用。
Nanocrystalline Mg2Ni and Mg1.7Al0.3N hydrogen storage alloys were prepared by solid-state diffusion and mechanical milling, and the electrochemical properties of the alloy were better than that prepared by the conventional method. The charge and discharge tests showed that the discharge voltage of the alloy was higher than 1 2V. When the discharge current density was 200 mA / g, the alloy was charged and discharged 50 times and the capacity remained above 200 mAh / g. X-ray diffraction analysis shows that: with the ball milling time, the diffraction peak broadening degree becomes larger, the intensity gradually weakened, 12 h after the change slowed down. This is due to the smaller grain size, increased defects and stress density. The improvement of the electrochemical properties of the alloy is related to the microstructure change of the alloy in the mechanical grinding, and the partial substitution of aluminum in the alloy composition plays an important role in prolonging the cycle life of the alloy.