影响Mg_2Ni储氢合金电极性能的因素分析

Influences of the Factors on Electrochemical Characteristics of Mg_2Ni Alloys

系统分析了球磨工艺、与 Mg粉球磨复合以及组元替换对 Mg2 Ni合金电极性能的影响。 X射线衍射分析和模拟电池法测试结果表明 ,Mg2 Ni合金的放电容量与球磨参数的选择密切相关 ,高的球磨能量有利于吸放氢的微结构迅速形成 ,故其放电容量显著提高。不同量的 Mg粉与 Mg2 Ni合金球磨制得Mgx/ Mg2 Ni复合合金 ,该类复合合金的放电容量随 Mg量的增加而有不同程度的提高。以 Nd部分替换Mg制得三元 Mg2 -x Ndx Ni合金 ,X为 0 .0 5和 0 .1时制得单相合金 ;X为 0 .2时制得由 Mg2 Ni、Nd Ni和Nd Mg Ni4相组成的三相合金。同 Mg2 Ni单相合金相比 ,包含 Mg2 Ni相的三元 Mg1.8Nd0 .2 Ni合金 ,球磨后它们的放电容量显著提高 ,这与 Nd Mg Ni4相的存在和球磨形成的多相复合微结构有关。

The effects of milling parameter,composites with Mg powder and element substitution with Nd on the electrochemical characteristics of Mg 2Ni alloys were investigated systematically in this paper. XRD analysis and the simulation battery testing on the alloys as negative electrodes show that, the discharge capacity of Mg 2Ni is closely associated with the microstructure, and a suitable microstructure can be rapidly formed with high energy ball milling, which enhanced hydrogen storage properties of Mg 2Ni alloys. It was found that the discharge capacity of Mg(x)/Mg 2Ni composite was obviously improved with increasing content of Mg powder in the milling. Both Mg 1.95Nd 0.05Ni and Mg 1.9Nd 0.1Ni alloys are single-phase, while three phases alloy (including Mg 2Ni?NdNi?NdMgNi 4) was formed in the preparation of Mg 1.8Nd 0.2Ni . An obvious enhancement in the discharge capacity was observed in Mg 1.8Nd 0.2Ni compared with Mg 2Ni alloy.It was suggested that the presence of NdMgNi 4 phase and composite mic- rostructure in alloys are crucial to the improvement of the discharge capacity.