• Journal of Institute of Convergence Technology
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• v.2 no.2
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• pp.25-29
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• 2012

Micro machining technologies have been required to satisfy various conditions in a high-technology industry. Micro electrochemical process is one of the most precision machining methods. Micro electrochemical process has been divided into electrochemical etching through protective layer and electrochemical machining using ultrashort voltage pulses. Micro shaft can be fabricated by electrochemical etching. The various protective layers such as photo-resist, oxide layer and oxidized recast layer have been used to protect metal surface during electrochemical etching. Micro patterning on metal surface can be machined by electrochemical etching through protective layer. Micro hole, groove and structures can be easily machined by electrochemical machining using ultrashort voltage pulses. Recently, the groove with subnanometer was machined using AFM.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.116-125
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• 2007

This article is concerned with synthesis, characterisation and electrochemical application of the mixed conducting perovskite type oxide to electrode materials for solid oxide fuel cell. First, this review provides a comprehensive survey of the various synthetic methods such as solid state reaction, Pechini, glycine nitrate process and sol-gel methods for the preparation of perovskite type oxide powders. Subsequently, the electrical and microstructural properties of the mixed conducting oxides were discussed in detail. Finally, as electrochemical applications of the mixed conducting perovskite type oxides to electrode materials for solid oxide fuel cell, fundamentals of theoretical ac-impedance model for porous mixed conducting electrodes were introduced. Furthermore, the ac-impedance behaviour of porous and dense mixed conducting electrodes prepared by various synthetic methods was discussed.

• Journal of Electrochemical Science and Technology
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• v.8 no.2
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• pp.96-100
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• 2017

Iridium(III) bis(2-phenylpyridinato-$N,C^{2^{\prime}}$)acetylacetonate ($(ppy)_2Ir(acac)$), a green dopant used in organic light-emitting devices (OLEDs), was subjected to electrochemical characterization to estimate its formal oxidation potential ($E^{o^{\prime}}$), HOMO energy level ($E_{HOMO}$), electron transfer rate constant ($k^{o^{\prime}}$), and diffusion coefficient ($D_o$). The employed combination of voltammetric methods, i.e., cyclic voltammetry (CV), chronocoulometry (CC), and the Nicholson method, provided meaningful insights into the electron transfer kinetics of $(ppy)_2Ir(acac)$, allowing the determination of $k^{o^{\prime}}$ and $D_o$. The quasi-reversible oxidation of $(ppy)_2Ir(acac)$ furnished information on $E^{o^{\prime}}$ and $E_{HOMO}$, allowing the latter parameter to be easily estimated by electrochemical methods without relying on expensive and complex ultraviolet photoemission spectroscopic (UPS) measurements.

• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.1-13
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• 2020

As research on secondary batteries becomes important, interest in analytical methods to examine the condition of secondary batteries is also increasing. Among these methods, the electrochemical impedance spectroscopy (EIS) method is one of the most attractive diagnostic techniques due to its convenience, quickness, accuracy, and low cost. However, since the obtained spectra are complicated signals representing several impedance elements, it is necessary to understand the whole electrochemical environment for a meaningful analysis. Based on the understanding of the whole system, the circuit elements constituting the cell can be obtained through construction of a physically sound circuit model. Therefore, this mini-review will explain how to construct a physically sound circuit model according to the characteristics of the battery cell system and then introduce the relationship between the obtained resistances of the bulk (R_b), charge transfer reaction (R_ct), interface layer (R_SEI), diffusion process (W) and battery characteristics, such as the state of charge (SOC), temperature, and state of health (SOH).

• Journal of Electrochemical Science and Technology
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• v.9 no.4
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• pp.301-307
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• 2018

The current study fabricated magnetic functional reduced graphene oxide (MFRGO) by relying on ${FeCl_4}^-$ magnetic anion confined to cationic 1-methyl imidazolium. Furthermore, for improving the electrochemical performance of conductive polymer, hybrid poly ortho aminophenol (POAP)/ MFRGO films have then been fabricated by POAP electropolymerization in the presence of MFRGO nanorods as active electrodes for electrochemical supercapacitors. Surface and electrochemical analyses have been used for characterization of MFRGO and POAP/ MFRGO composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. Prepared composite film exhibited a significantly high specific capacity, high rate capability and excellent cycling stability (capacitance retention of ~91% even after 1000 cycles). These results suggest that electrosynthesized composite films are a promising electrode material for energy storage applications in high-performance pseudocapacitors.

• 한국전기화학회:학술대회논문집
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• 2004.04a
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• pp.27-27
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• 2004

• 한국전기화학회:학술대회논문집
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• 2003.04a
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• pp.33-33
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• 2003

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.1-7
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• 2024

With the increasing demand for wearable sensors that are capable of point-of-care testing, paper-based sensors have been extensively studied. Paper is not only extremely cost-effective but also lightweight and flexible, and it is easy to apply conductive materials such as carbon and hydrophobic substances like wax to its surface. Moreover, the capillary action caused by cellulose fibers in paper allows the flow of liquid without help from external forces, making paper a particularly promising platform for wearable electrochemical sensors. Accordingly, paper-based sensors for detecting various analytes through electrochemical methods have been actively developed. Recently, paper-based electrochemical sensors that utilize electrochemiluminescence (ECL) or electrochromic materials for the optical read-out have been reported. This review introduces the basic fabrication methods and various application strategies of paper-based electrochemical sensors.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.5
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• pp.795-799
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• 2013

This paper describes a novel hybrid surface polishing process combining non-traditional electrochemical polishing (ECP) with external artificial ultrasonic vibration. The purpose of this study is to develop an easier method for improving stainless steel surfaces. To this end, vibration electrochemical polishing (VECP), a novel ultrasonic manufacturing process, for enhancing electrochemical reaction and surface quality compared with that achieved using conventional ECP is suggested. In addition, for finding the optimized experimental conditions, the two methods are compared under various current densities. Localized roughness of the work material is measured with atomic force microscopy (AFM) and scanning electron microscopy (SEM) for obtaining detailed surface information.

• Journal of Electrochemical Science and Technology
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• v.9 no.2
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• pp.149-156
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• 2018

In this technical note, I report the analysis of electrochemical impedance data measured with potential sweeping. Even though the instruments for voltammetric impedance measurements have been developed for decades using different approaches, their applications are limited due to the lack of well-established protocols to easily analyze voltammetry data. To fill this gap, the singular point of the specific potential is considered that is only determined by the standard/formal potential and the transfer coefficient and is independent of the kinetics and experimental parameters (including revertability) of faradaic reactions. Taking the advantage of its inertness, I suggest an approach employing the singular point as a reference to obtain general electrochemical information. As all the concepts and methods are verified with numerical simulations, this technique is expected to be applied for complex reactions involving electrochemical and chemical reaction mechanisms.