• Membrane Journal
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• v.33 no.3
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• pp.137-147
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• 2023

In this study, Br-PPO was developed by applying additive organic particles through a suspension polymerization synthesis method. The anion exchange membrane fuel cell system performance was evaluated using it to an anion exchange membrane. To improve the performance, organic ion exchange particles were prepared and added to the anion exchange membrane. Chemical structure analysis and synthesis were determined through FT-IR and NMR, and tensile strength and thermal stability were measured through TGA and UTM to determine whether it could be driven. Before the anion exchange membrane fuel cell test, the performance was evaluated by measuring the ion conductivity and ion exchange capacity. Finally, the Br-PPO-TMA-SDV (0.7%) anion exchange membrane with excellent ion conductivity and ion exchange capacity was introduced into the fuel cell system. Its performance was compared with FAA-3-50, a commercial membrane, to determine whether it could be introduced into a fuel cell system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.19-26
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• 2010

A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be coped with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. The thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, thermal management system of PEMFC stack is modeled to understand the dynamic response during load change. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. The different operating strategy is applied for each cooling circuit considering the duty of those two circuits. Even though the capacity of PEMFC system (1kW) is enough to supply hot domestic water for residence, heat-up of reservior takes some hours. Therefore, in this study, time schedule of the simulation reflects the heat-up process. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

• Membrane Journal
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• v.26 no.5
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• pp.329-336
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• 2016

Proton exchange membrane (PEM) is one of the key components of membrane-electrode assembly (MEA), which plays important role in fuel cell performance together with catalysts. It is widely accepted that water channel morphology inside PEMs as a proton pathway significantly affects the PEM performance. Molecular dynamics (MD) simulations are a very useful tool to understand molecular and atomic structures of materials, so that many related researches are currently being studied. In this paper, we summarize the current research trend in MD simulations, present which properties can be characterized, and finally introduce the usefulness of MD simulations to the researchers for proton exchange membranes.

• Membrane Journal
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• v.29 no.3
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• pp.173-182
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• 2019

Much research has been made for finding new and eco-friendly alternative sources of energy to solve the problems related with the pollution caused by emissions of greenhouse gases such as carbon dioxide as the use of fossil fuels increases worldwide. Among them, fuel cells draws particular interests as an eco-friendly energy generator because only water is obtained as a by-product. Anion exchange membrane-based alkaline fuel cell (AEMFC) that uses anion exchange membrane as an electrolyte is of increased interest recently because of its advantages in using low-cost metal catalyst unlike the PEMFC (potton exchange membrane fuel cell) due to the high-catalyst activity in alkaline conditions. The main properties required as an anion exchange membrane are high hydroxide conductivity and chemical stability at high pH. Recently we reported a chemically crosslinked poly(2-dimethyl-1,4-phenylene oxide) (PPO) by reacting PPO with N,N,N',N'-tetramethyl-1,6-hexanediamine as novel anion exchange membranes. In the current work, we further developed the same crosslinked polymer but having enhanced physicochemical properties, including higher conductivity, increased mechanical and dimensional stabilities by using the PPO with a higher molecular weight and also by increasing the crosslinking density. The obtained polymer membrane also showed a good cell performance.

• Membrane Journal
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• v.32 no.4
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• pp.209-217
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• 2022

Ion exchange membrane (IEM) is an important class of membrane applied in batteries, fuel cells, chloride-alkali processes, etc to separate various mono and multivalent ions. The membrane process is based on the electrically driven force, green separation method, which is an emerging area in desalination of seawater and water treatment. Electrodialysis (ED) is a technique in which cations and anions move selectively along the IEM. Anion exchange membrane (AEM) is one of the important components of the ED process which is critical to enhancing the process efficiency. The introduction of cross-linking in the IEM improves the ion-selective separation performance due to the reduction of free volume. During the desalination of seawater by reverse osmosis (RO) process, there is a lot of dissolved salt present in the concentrate of RO. So, the ED process consisting of a monovalent cation-selective membrane reduces fouling and improves membrane flux. This review is divided into three sections such as electrodialysis (ED), anion exchange membrane (AEM), and cation exchange membrane (CEM).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.601-602
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• 2013

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1173-1182
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• 2018

Mesoporous silica allows proper hydration of an ion exchange membrane under low relative humidity due to its strong hydrophilicity and structural characteristic. A mesoporous silica and Nafion composite membrane shows good proton conductivity under low relative humidity. An understanding of ion-channel formation and proton transfer through an ion-channel network in mesoporous silica and Nafion composite membranes is essential for the development and the optimization of ion exchange membranes. In this study, a mesoporous cellular foam $SiO_2/Nafion$ composite membrane is fabricated, and its proton conductivity and performance are measured. Also, the ion-channel distribution is analyzed by using electrostatic force microscopy to measure the surface charge density of the mesoporous cellular foam $SiO_2/Nafion$ composite membrane. The research reveals a few remarkable results. First, the composite membrane shows excellent proton conductivity and performance under low relative humidity. Second, the composite membrane is observed to form ion-channel-rich and ion-channel-poor region locally.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.1-8
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• 2014

Ion exchange membrane is widely used in various fields such as electro dialysis, diffusion dialysis, redox flow battery, fuel cell. PVC cation exchange membrane using ultrasonic modification was prepared by sulfonation reaction in various sulfonation times. Sulfuric acid was used as a sulfonating agent with ultrasonic condition. We've characterized basic structure of sulfonated PVC cation exchange membrane by FT-IR, EDX, water uptake, ion exchange capacity (IEC), electrical resistance (ER), conductivity, ion transport number and surface morphology (SEM). The presence of sulfonic groups in the sulfonated PVC cation exchange membrane was confirmed by FT-IR. The maximum values of water uptake, IEC, electrical resistance and ion transport number were 40.2%, 0.87 meq/g, $35.2{\Omega}{\cdot}cm^2$ and 0.88, respectively.

• Membrane Journal
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• v.31 no.6
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• pp.371-383
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• 2021

Anion exchange membranes have been used for water electrolysis, which can produce hydrogen, and fuel cells, which can generate electrical energy using hydrogen fuel. Anion exchange membranes operate based on hydroxide ion (OH^-) conduction under alkaline conditions. However, since the anion exchange membrane shows relatively low ion conductivity and alkaline stability, there is still a limit to its commercialization in water electrolysis and fuel cells. To address these issues, it is important to develop novel anion exchange membrane materials by rationally designing a polymer structure. In particular, the polymer structure and synthetic method need to be controlled. By doing so, for polymers, the physical properties, ionic conductivity, and alkaline stability can be maintained. Among many anion exchange membranes, poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is commercially available and easily accessible. In addition, the PPO has relatively high mechanical and chemical stability compared to other polymers. In this review, we introduce the recent development strategy and characteristics of PPO-based polymer materials used in anion exchange membranes.

• Membrane Journal
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• v.30 no.2
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• pp.79-96
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• 2020

Secondary energy conversion systems have been briskly developed owing to environmental issue and problems of fossil fuel. They are basically operated based on electro-chemical systems. In addition, ion exchange membranes are one of the significant factors to determine performance in their systems. Therefore, the ion exchange membranes in suitable conditions must be developed to improve the performance for the electro-chemical systems. These ion exchange membranes can be classified into various types such as cation exchange membrane, anion exchange membrane and bipolar membrane. Their membranes have distinct characteristics according to the chemical, physical and morphological structure. In this review, the types of ion exchange membranes and their fabrication processes are described with main characteristics. Moreover, applications of ion exchange membranes in newly developed energy conversion systems such as reverse electrodialysis, redox flow battery and water electrolysis process are described including their roles and requirements.