Application of Anodizing Method Templates for Electrochemical Capacitors
Lithium ion batteries (LIBs) and electro double layer capacitors (EDLCs) are regarded as electrical energy storage systems (ESS). LIBs are high energy density, but EDLCs have low energy density general information. The lithium ion capacitor (LIC) has advantages of LIBs and EDLCs. LIC has high energy density, high power density and high safety than LIBs. LIC comprises of a cathode electrode; active carbon, anode; graphitized carbon. It is similar to LIB and EDLC.
Porous anodic oxide films of aluminum (anodic porous alumina) have been widely investigated as nano templates and resist-films with good insulating properties for various micro and nano technology applications, such as magnetic recording media, electronic devices, biosensors, photonic crystals, micro lens arrays, plasmonic devices, three-dimensional microstructures and other basic nano-devices. When aluminum is anodized in appropriate acidic electrolytes, porous alumina develops, which exhibits a uniform array of hexagonal cells, each containing a uniform cylindrical nano-pore at the center.
In this study, we prepared carbon nano fibers (CNFs) by anodizing method on anodized alumina oxide (AAO) templates that were anodized in oxalic acid at 40V or phosphoric acid at 195V. These two types anodizing conditions determine the pore size of AAO and diameter of CNF. Mixture of anodic porous templates and PAA was carbonized in nitrogen at 600°C. The CNFs were heated up to 1400°C to increase the crystalline.
We have discussed the effect of diameter change of CNFs on the electrochemical properties as an anode material in LICs. CNFs were prepared by carbonization using precursors with the polymer. Surface morphology of AAO templates and prepared CNFs were investigated by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The physical properties were performed by X-ray diffraction (XRD) and nitrogen gas adsorption measurements.
The electrode was prepared by slurry type. Electrochemical properties were evaluated that cyclic voltammetry (CV), electrochemical impedance spectroscope (EIS) and charge-discharge test.
Result & Discussion
Figure 1 shows the SEM images of Anodized Alumina Templates, (a) anodized at phosphoric acid, (b) anodized at oxalic acid
Figure shows SEM images of the AAO templates after pore-expansion treatment with 2nd anodized AAO templates at different electrolyte. The results of the electrolyte change bring result that change of pore size of AAO templates can be seen clearly. and we can prepared that the CNFs by AAO template shows a well-ordered diameter. The CNFs were heated up to 600, 1000, and 1400°C to increase the crystallite degree. As results, we confirmed that CNF has become platelet structure.