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为了研究Mg3MnNi2储氢合金的电化学储氢性能,实验采用Co元素部分取代Mg3MnNi2合金中的Ni,用固相扩散法制备出Mg3MnNi2-xCox(x=0~0.2)系列合金,并分析其相结构,以及测试合金的电化学性能和动力学性能。结果表明:Co元素的添加并不改变合金的主相,Co替代Ni明显改善了合金的放电容量、循环稳定性以及动力学性能等,其中当Co的含量从0增加到0.2时,合金的最大放电容量达到最大值282.36mA·h/g,20次循环后容量保持率仍有74.7%,而且动力学性能也是最优,高倍率放电性能ηHRD从66.4%增长到73.3%。这主要是Co替代Ni能够降低生成氢化物的稳定性,提高合金的抗粉化能力,以及降低合金的极化电阻。
In order to study the electrochemical hydrogen storage properties of Mg3MnNi2 hydrogen storage alloy, the Co element partially substituted Ni in Mg3MnNi2 alloy, the Mg3MnNi2-xCox (x = 0 ~ 0.2) alloy was prepared by solid-state diffusion method and the phase structure , As well as testing the electrochemical and kinetic properties of the alloy. The results show that the addition of Co element does not change the main phase of the alloy, and the substitution of Co for Ni significantly improves the discharge capacity, cycle stability and kinetic properties of the alloy. When the Co content increases from 0 to 0.2, the maximum The discharge capacity reached the maximum value of 282.36mA · h / g. After 20 cycles, the capacity retention ratio remained at 74.7%, and the kinetic performance was also optimized. The high-rate discharge characteristic ηHRD increased from 66.4% to 73.3%. This is mainly due to the substitution of Co for Ni to reduce the stability of the resulting hydride, increase the anti-chalking ability of the alloy, and reduce the polarization resistance of the alloy.