纳米结构氢氧化镍粉末对镍电极的改性作用

采用水溶液化学沉淀法直接合成了具有纳米结构特征的氢氧化镍粉末,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、BET比表面积等方法对其结构特征进行了表征。将纳米结构氢氧化镍粉末以一定比例添加到商用球形氢氧化镍粉末中作为活性材料制备发泡式镍电极,采用恒电流充放电测试、循环伏安(CV)及交流阻抗分析(EIS)等方法对镍电极的电化学性能进行了研究。结果表明,纳米结构氢氧化镍粉末的添加可以使镍电极在充电效率、放电比容量、活性物质利用率、放电电压、抗膨胀能力及高速率放电性能等方面得到明显改善和提高。添加有纳米结构粉末的镍电极具有更高的反应活性及更小的电化学反应阻抗,充电时氧气析出电位也比较高,因而表现出优良的电化学性能。

Effects of nanostructured nickel hydroxide powder on the electrochemical performance of pasted nickel electrodes

Nanostructured nickel hydroxide powder had been synthesized by an aqueous solution chemical precipitation method, and the structural characteristics of the synthesized material were analyzed by SEM, XRD and BET. The pasted foam-nickel electrodes had been prepared with a mixture of the nanostructured and spherical Ni(OH)2 powders as the active material. Constant current charge/discharge tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrochemical performances of the pasted nickel electrodes. The experimental results show that in comparison with that of the spherical Ni(OH)2 electrode, the nickel electrodes with the addition of the nanostructured Ni-(OH)2 exhibit better performances in the charge efficiency, dicharge specific capacity, active material utilization, discharge voltage, resistance to swelling with cycling and high-rate capability. These superior performances can be attributed to the higher reaction activity, lower electrochemical impedance and higher oxygen evolution potential for the nanostructured nickel hydroxide electrodes.