• The Journal of the Korea Contents Association
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• v.2 no.1
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• pp.120-124
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• 2002

It is the purpose of the present to report result of a preliminary electrochemical characterization of the as-cast Mg-Ca alloys. Electrochemical data will be correlated with chemical composition of impurities, and the microstructural change before and after Ca is added. This paper shows that small addition of Ca imparts beneficial effect in electrochemical properties of Mg alloy, primarily, through microstructural modifications.

• Journal of Electrochemical Science and Technology
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• v.3 no.4
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• pp.172-177
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• 2012

Mo-doped $LiFePO_4$ was synthesized via co-precipitation method using sucrose as the carbon source. Structure, surface morphology, and the electrochemical properties of the synthesized olivine compounds were investigated using Rietveld refinement of X-ray diffraction data (XRD), scanning electron microscopy (SEM), and electrochemical charge-ischarge tests. Spherical morphology with the particle size of ${\sim}8{\mu}m$ authenticated the enhanced tap density and volumetric energy density of the synthesized materials. Charge-discharge behavior of $LiFePO_4$ and Mo-doped $LiFePO_4$ cells demonstrated a specific capacity of 130 and 145 mAh $g^{-1}$, respectively. Mo-doped $LiFePO_4$ cells exhibited an excellent discharge capacity at 96 mAh $g^{-1}$ at 7 C-rate.

• 한국전기화학회:학술대회논문집
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• 2003.07a
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• pp.83-88
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• 2003

PtRu alloy and $PtRu-WO_3$ nanocomposite thin-film electrodes for methanol electrooxidation were fabricated by means of a sputtering method. The structural and electrochemical properties of well-defined PtRu alloy thin-film electrodes were characterized using X-ray diffraction, Rutherford backscattering spectroscopy. X-ray photoelectron spectroscopy, and electrochemical measurements. The alloy thin-film electrodes were classified as follows: Pt-based and Ru-based alloy structure. Based on structural and electrochemical understanding of the PtRu alloy thin-film electrodes, the well-controlled physical and (electro)chemical properties of $PtRu-WO_3$, showed superior specific current to that of a nanosized PtRu alloy catalyst, The homogeneous dispersion of alloy catalyst and well-formed nanophase structure would lead to an excellent catalytic electrode reaction for high-performance fuel cells. In addition, the enhanced catalytic activity in nanocomposite electrode was found to be closely related to proton transfer in tungsten oxide using in-situ electrochemical transmittance measurement.

• Journal of Electrochemical Science and Technology
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• v.13 no.4
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• pp.486-496
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• 2022

The effect of solution-treated on the self-corrosion performance and discharge performance of AZ91 magnesium alloy as anode material was analyzed by microscopic characterization, immersion tests, electrochemical measurements, and discharge performance tests. The study shows that the β-phase in the AZ91 magnesium alloy gradually dissolved in the matrix with the increase of the solution temperature, and the electrochemical activity of the magnesium alloy anode was significantly improved. Through the comparison of three different solution-treated processes, it is found that the AZ91 magnesium alloy has the most vigorous activity and better discharge performance after solution-treated of 415℃+12 h. In addition, the proportion and distribution of β-phase AZ91 magnesium alloy have a direct impact on its discharge performance as an anode material.

• Journal of Electrochemical Science and Technology
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• v.7 no.4
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• pp.316-326
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• 2016

Development and discovery of efficient, cost-effective, and robust electrocatalysts are imperative for practical and widespread implementation of water electrolysis and fuel cell techniques in the anticipated hydrogen economy. The electrochemical reactions involved in water electrolysis, i.e., hydrogen and oxygen evolution reactions, are complex inner-sphere reactions with slow multi-electron transfer kinetics. To develop active electrocatalysts for water electrolysis, the physicochemical properties of the electrode surfaces in electrolyte solutions should be investigated and understood in detail. When electrocatalysis is conducted using nanoparticles with large surface areas and active surface states, analytical techniques with sub-nanometer resolution are required, along with material development. Scanning electrochemical microscopy (SECM) is an electrochemical technique for studying the surface reactions and properties of various types of electrodes using a very small tip electrode. Recently, the morphological and chemical characteristics of single nanoparticles and bio-enzymes for catalytic reactions were studied with nanometer resolution by combining SECM with atomic force microscopy (AFM). Herein, SECM techniques are briefly reviewed, including the AFM-SECM technique, to facilitate further development and discovery of highly active, cost-effective, and robust electrode materials for efficient electrolysis and photolysis.

• Journal of Electrochemical Science and Technology
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• v.2 no.3
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• pp.180-185
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• 2011

The layered lithium-manganese oxide ($Li_2MnO_3$) as a cathode material of lithium ion secondary batteries was prepared and characterized the physico-chemical and electrochemical properties. The morphological and structural changes of MnO(OH) and $Li_2MnO_3$ are closely connected to the changes of electrochemical properties. The crystallinity of $Li_2MnO_3$ is enhanced as the annealing temperature increase, but its capacity is reduced due to the easier structural changes of less crystalline $Li_2MnO_3$ than highly crystalline one. Moreover, the addition of buffer material such as MnO(OH) into cathode causes to reduce the morphological and structural changes of layered $Li_2MnO_3$ and increase the discharge capacity and cycleability.

• 한국전기화학회:학술대회논문집
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• 2002.10a
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• pp.19-19
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• 2002

• 한국전기화학회:학술대회논문집
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• 2001.04a
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• pp.9-9
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• 2001

• 한국전기화학회:학술대회논문집
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• 1998.12a
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• pp.41-58
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• 1998

• 한국전기화학회:학술대회논문집
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• 2002.04a
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• pp.9-9
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• 2002