Qorbani Mohammad, Naseri Naimeh, Moshfegh Alireza Z
†Department of Physics, Sharif University of Technology, Tehran 11155-9161, Iran.
‡School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
ACS Appl Mater Interfaces. 2015 Jun 3;7(21):11172-9. doi: 10.1021/acsami.5b00806. Epub 2015 May 21.
In this research, facile and low cost synthesis methods, electrodeposition at constant current density and anodization at various applied voltages, were used to produce hierarchical cobalt oxide/hydroxide nanoflakes on top of porous anodized cobalt layer. The maximum electrochemical capacitance of 601 mF cm(-2) at scan rate of 2 mV s(-1) was achieved for 30 V optimized anodization applied voltage with high stability. Morphology and surface chemical composition were determined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The size, thickness, and density of nanoflakes, as well as length of the porous anodized Co layer were measured about 460±45 nm, 52±5 nm, 22±3 μm(-2), and 3.4±0.3 μm for the optimized anodization voltage, respectively. Moreover, the effect of anodization voltage on the resulting supercapacitance was modeled by using the Butler-Volmer formalism. The behavior of the modeled capacitance in different anodization voltages was in good agreement with the measured experimental data, and it was found that the role and contribution of the porous morphology was more decisive than structure of nanoflakes in the supercapacitance application.
在本研究中，采用简便且低成本的合成方法，即恒电流密度电沉积和不同施加电压下的阳极氧化，在多孔阳极氧化钴层顶部制备了分级钴氧化物/氢氧化物纳米片。在2 mV s(-1)的扫描速率下，对于30 V优化阳极氧化施加电压，实现了601 mF cm(-2)的最大电化学电容，且具有高稳定性。通过扫描电子显微镜(SEM)和X射线光电子能谱(XPS)分析确定了形态和表面化学成分。对于优化的阳极氧化电压，纳米片的尺寸、厚度和密度以及多孔阳极氧化钴层的长度分别测量为约460±45 nm、52±5 nm、22±3 μm(-2)和3.4±0.3 μm。此外，利用Butler-Volmer形式主义对阳极氧化电压对所得超级电容的影响进行了建模。模拟电容在不同阳极氧化电压下的行为与实测实验数据吻合良好，并且发现在超级电容应用中，多孔形态的作用和贡献比纳米片结构更具决定性。
