电化学氧化工艺对NiO/Ni(OH)2电极材料电容性能的影响

Effect of electrochemical oxidation process on capacitance properties of NiO/Ni(OH)2 electrode materials

通过化学镀再电化学氧化的方法在铜片表面制备出带有微坑的均一NiO/Ni(OH)2电极材料,采用扫描电镜、X射线衍射、X射线光电子能谱和电化学技术对所制备的NiO/Ni(OH)2电极材料进行表征和电化学性能测试。结果表明,所制备的电极材料由Ni、NiO和Ni(OH)2组成,电化学氧化电解液中添加2种助氧化剂过硫酸钾和亚硝酸钠均能提高NiO/Ni(OH)2电极材料的比电容值50%~69%;在1 A/g的充放电电流密度下,2种助氧化剂存在下阳极氧化所制得的NiO/Ni(OH)2电极材料经历10000次充放电循环后分别给出了1410 F/g和1380 F/g的比电容,显示出良好的可逆性及电化学稳定性。化学镀表面的非晶组织和添加助氧化剂进行电化学原位氧化使得表面氧化物含量增大及致密性提高是其显示优异赝电容性能的主要原因。

Homogeneous NiO/Ni(OH)2 electrode materials with micropits were prepared on the surface of copper sheet by electroless-electrochemical anodic oxidation.SEM,XRD and XPS test results show that the prepared electrode materials are composed of Ni,NiO and Ni(OH)2,and the addition of two assistant oxidants(K2S2O8 and NaNO2)in the electrochemical anodic oxidation electrolyte can improve the surface NiO/Ni(OH)2 content of the electrode materials.Cyclic voltammetry measurements show that the specific capacitance of NiO/Ni(OH)2 electrode materials are increased by 50%~69%with the addition of two kinds of assistant oxidants.At the charge/discharge current density of 1 A/g,the specific capacitance of 1410 F/g and 1380 F/g are obtained by anodic oxidation of the NiO/Ni(OH)2 electrode material in the presence of two kinds of assistant oxidants after 10000 charge/discharge cycles,showing good reversibility and electrochemical stability.The Ragone curves reveals that the prepared NiO/Ni(OH)2 samples have higher power density and lower energy density.The electroless Ni plating is amorphous structure,and the content of surface oxide is increased by in-situ electrochemical anodic oxidation with the addition of two kinds of assistant oxidants.These factors are responsible for the superior pseudocapacitive performance of NiO/Ni(OH)2 electrode materials.