正交实验法研究电沉积Mg-Ni储氢合金的制备工艺

Study on the Preparation Technology of Electrodeposited Mg-Ni Hydrogen Absorbing Alloy by Using Orthogonal Tests

采用正交实验法研究了电沉积制备Mg-Ni型储氢合金的工艺条件。结果表明,各因素影响合金放电比容量的次序为:温度>氯化镁含量>次磷酸钠含量>电流密度>柠檬酸钠含量。得到的最佳电沉积工艺为:氯化镁含量180 g/L,柠檬酸钠含量60 g/L,次磷酸钠含量70 g/L,氯化镍含量30 g/L,硼酸含量30 g/L,电流密度100 mA/cm2,温度45℃,pH 3～4。此时制备的合金放电比容量达到250 mAh/g,有较为明显的充放电平台,首次充放电即达到最大容量;但随着循环次数的增加,放电容量下降较快。XRD分析表明,电沉积得到非晶态的Mg2Ni+Ni合金。

The preparation technology of electrodeposited Mg-Ni hydrogen absorbing alloy was studied by using orthogonal tests in this paper. The results show that according to the purpose of higher special discharge capacity, the descending order of the influencing factors is, temperature, content of MgCl2, content of NaH2PO2, current density and content of C6H5Na3O7. The discharge capacity of the alloy reaches 250 mAh/g under the depositing conditions of current density 100 mA/cmz, temperature 45℃, content of MgCI2 180 g/L, NaH2PO2·H20 70 g/L, C6HsNa3OT-H2O 60 g/L, NiCl2 30 g/L, H3BO3 30 g/L and pH 3 - 4. It has obvious charge-discharge platforms and its capacity reaches the maximum in the first charge-discharge cycle but falls fast with the increase of cycles. The result of XRD shows that the alloy is composed of amorphous Mg2Ni ＋ Ni phases.