• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1129-1131
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• 2002

Zinc Air battery obtain their energy density advantage over the other batteries by utilizing ambient oxygen as the cathode materials, and reusing cathode as recycled form. And specific capacity of zinc powder is as high as 820mAh/g. When Zinc Air battery discharged by low rate current discharge voltage profile has very flat pattern until end of voltage. But, when Zinc Air battery discharged by high rate current discharge voltage and capacity become lower. Therefore, we focused on effects of catalyst size in cathode. So we examined performance of zinc air batteries, average discharge voltage, capacity, energy, resistance. And we also obtained resistance by the GSM pulse discharge. So we have got optimum size of catalyst for Zinc Air battery.

• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.26-32
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• 2020

In this study, the side reactions that greatly affect the coulombic efficiency of a zinc-air secondary battery are quantitatively analyzed on the basis of the charging-discharging characteristics, open circuit self-discharge characteristics, and a series of calculations. In particular, the charge amounts consumed by water electrolysis and self-discharge during charging process are separately determined so that the charging efficiency (the amount of charge used in actual charging with respect to the applied charge amount) can be estimated, which would enable systematic understanding of the cause of coulombic efficiency degradation. Using two cells with different charging overvoltages, the validity of the proposed method can be assessed.

• Journal of the Korean Electrochemical Society
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• v.16 no.1
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• pp.9-18
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• 2013

Components of zinc-air battery and their problems are explained. Energy density of zinc air battery is superior to other commercial ones including Li-ion batteries. Cycle life of the zinc air batteries is poor because of irreversible redox reactions on both electrodes. In order to improve the performance of the zinc air battery, catalysts, passivation, and the new structure of electrodes should be developed to optimize several reactions in an electrode. Multidisciplinary efforts, such as mechanics, corrosion science, composite materials are necessary from the beginning of the research to obtain a meaningful product.

• Ceramist
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• v.21 no.4
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• pp.312-330
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• 2018

Energy storage/conversion has become crucial not only to meet the present energy demand but also more importantly to sustain the modern society. Particularly, electrical energy storage is critical not only to support electronic, vehicular and load-levelling applications but also to efficiently commercialize renewable energy resources such as solar and wind. While Li-ion batteries are being intensely researched for electric vehicle applications, there is a pressing need to seek for new battery chemistries aimed at stationary storage systems. In this aspect, Zn-ion batteries offer a viable option to be utilized for high energy and power density applications since every intercalated Zn-ion yields a concurrent charge transfer of two electrons and thereby high theoretical capacities can be realized. Furthermore, the simplicity of fabrication under open-air conditions combined with the abundant and less toxic zinc element makes aqueous Zn-ion batteries one of the most economical, safe and green energy storage technologies with prospective use for stationary grid storage applications. Also, Zn-ion batteries are very safe for next-generation technologies based on flexible, roll-up, wearable implantable devices the portable electronics market. Following this advantages, a wide range of approaches and materials, namely, cathodes, anodes and electrolytes have been investigated for Zn-ion batteries applications to date. Herein, we review the progresses and major advancements related to aqueous. Zn-ion batteries, facilitating energy storage/conversion via $Zn^{2+}$ (de)intercalation mechanism.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.203-207
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• 2003

Zinc Air batteries obtain their energy density by utilizing ambient oxygen as the cathode materials. And specific capacity of zinc powder is as high as 820 mAh/g. When Zinc Air battery discharged at low current, then discharge voltage profile has very flat pattern until reach to end of voltage. But, when Zinc Air battery discharged at high current, then discharge voltage and energy becomes very low. So we focused on resistance and porosity of cathode with contents of PTFE. Wf studied on the effects of PTFE on performance of Zinc Air batteries. So we have got optimum contents of PTFE binder.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.2
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• pp.148-155
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• 2015

Electrospun $LaCoO_3$ perovskite nanofibers were produced for the air electrode in Zn-air rechargeable batteries using electrospinning technique with sequential calcination. The final calcination temperature was varied from 500 to $800^{\circ}C$ in order to determine its effect on the physical and electrochemical properties of the prepared $LaCoO_3$ perovskite nanofibers. The surface area of the electrospun $LaCoO_3$ perovskite nanofibers were observed to decrease with increasing final calcination temperature. Electrospun $LaCoO_3$ perovskite nanofibers calcined with final calcination temperature of $700^{\circ}C$ had the best electrocatalytic activity among the prepared perovskite nanofibers.

• Membrane Journal
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• v.24 no.3
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• pp.231-239
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• 2014

Polyetherimide (PEI) membranes for separators in Zn air batteries were prepared via phase inversion process from casting solution composed of PEI, n-methylpyrolidone (NMP), and polyvinylpurrolidone (PVP). Furthermore, Zn air batteries were fabricated with the separators. The effects of PEI content and PVP addition in the casting solution on the morphology, mechanical strength, ionic conductivity were investigated through SEM, stress-strain test and ac impedance test. The elelctrochemical performances of the batteries were evaluated through galvanostatic discharge analysis. The mechanical strength of the membrane increased with increasing PEI composition in the casting solution. Little effect of PVP addition into the solution on the mechanical strength of the membrane was investigated. The ionic conductivity value decreased with increasing PEI composition in the solution. With addition of PVP, ionic conductivity of membrane increased until 10 wt% to show the maximum value of 0.1 S/cm. In the higher range of PVP addition over 10%, the ionic conductivity decreased with increasing PVP addition. Ionic conductivity of separator strongly affected the capacity of Zn air battery, and the battery assembled with the separator which showed high ionic conductivity showed high capacity.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.74-78
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• 2002

Zinc Air battery obtain their energy density advantage over the other batteries by utilizing ambient oxygen as the cathode materials, and reusing cathode as recycled form. And specific capacity of zinc powder is as high as 820 mAh/g. However, if the pore size in cathode is small then the flow rate of air decreased, and as a result of that discharge voltage of batteries becomes low. We focused on resistance and porosity of cathode. So we studied the effects of conducting agents to zinc air batteries performance, capacity, power density, average discharge voltage, resistance. And we also measured porosity of cathode by the ASTM. So we have got optimum contents of conducting agent.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.436-442
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• 2014

$LaCoO_3$ powders synthesized by Pechini process were pulverized by planetary ball-milling to decrease particle size and characterized as a catalyst in alkaline solution for oxygen reduction and evolution reaction (ORR & OER). The changes of physical properties, such as particle size distribution, surface area and electric conductivity, were analyzed as a function of ball-milling time. Also, the variations of the crystal structure and surface morphology of ball-milled powders were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemically catalytic activities of the intrinsic $LaCoO_3$ powders decreased with increasing ball-milling time, but their electrochemical performance as an electrode improved by the increase of the surface area of the powder.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.98-106
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• 2022

Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co²⁺ or Zn²⁺ and linkers such as imidazole or imidazole derivatives. ZIF-67, composed of Co²⁺ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbon-based materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.