两步法制备Mg-Ni系贮氢合金及其表面改性

Preparation of Mg-Ni hydrogen storage alloy by two-step method and its surface modification

采用先在高温下烧结使元素充分扩散,然后再球磨的两步法制备了一系列的Mg Ni系贮氢合金Mg2Ni、Mg1.7 Al0.3Ni、Mg1.7Ti0.3Ni和Mg1.9Ti0.1Ni0.8Al0.2,研究了将Mg2Ni用Ti、Al部分替换Mg和化学镀对合金电极的影响,并对试样进行了XRD分析和电化学性能测量。结果表明Mg1.7Al0.3Ni合金中形成一种新相,该相具有面心立方结构,晶格常数为0.604nm,Mg1.7Al0.3Ni的电化学容量较高,这应与这种新相的形成有关。这一结论对用两步法制备Mg Ni系贮氢合金有意义。该合金经次磷酸钠作还原剂的碱性化学镀镍后,电化学容量有非常明显的提高,但对循环稳定性的改善不明显。

A series of MgNi hydrogen storage alloy, such as Mg2Ni, Mg1.7Al0.3Ni,Mg1.7Ti0.3Ni and Mg1.9Ti0.1Ni0.8Al0.2 were prepared by the twostep method, i.e. sintering metals pellet at high temperature, then mill it to powder. The effects of the chemical plating and partial substitution of Ti and Al for Mg in Mg2Ni on the performance of alloy electrode were discussed. The results of XRD analysis and electrochemical property measurement show that Mg1.7Al0.3Ni has high electrochemical capacity and a new phase is formed in it. The new phase is in facecentered cubic structure and its lattice constant is 0.604 nm. This result is instructional for preparing MgNi hydrogen storage alloy by the twostep method. And the electrochemical capacity of Mg1.7Al0.3Ni is increased obviously by the alkaline electroless plating of nickel, which use sodium hypophosphite as reductant, whereas its cycle life is not improved greatly.