• Ceramist
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• v.22 no.2
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• pp.182-188
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• 2019

Alternative energy sources to the systems using hydrocarbon fuels have been actively developed due to exhaustion of fossil fuels and issue of global warming by CO₂. Fuel cells have attracted great attentions to solve these issues as electricity can be produced with product of clean H₂O by using H₂-O₂ as a fuel. Besides, using reverse reactions make it possible to produce H₂ and O₂ gas from electrolysis of water. There are various fuel cells systems depending on the types of electrolyte, and in this mini-reviews, the main aim is to focus on perovskite oxides as a catalyst for oxygen-evolution reactions in alkaline electrolysis and its potential to application of alkaline electrolysis systems.

• Journal of Electrochemical Science and Technology
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• v.5 no.3
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• pp.73-81
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• 2014

This paper describes the continuous flow operation of membraneless sodium perborate fuel cell using acid/alkaline bipolar electrolyte. Here, hydrazine is used as a fuel and sodium perborate is used as an oxidant under Alkaline-acid media configuration. Sodium perborate affords hydrogen peroxide in aqueous medium. In our operation, the laminar flow based microfluidic membranleless fuel cell achieved a maximum power density of $27.2mW\;cm^{-2}$ when using alkaline hydrazine as the anolyte and acidic perborate as the catholyte at room temperature with a fuel mixture flow rate of $0.3mL\;min^{-1}$. The simple planar structured membraneless sodium perborate fuel cell enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable power applications.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.77-80
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• 2006

Chloromethylated polysulfone(CMPSf) and a number of mono- and diamine compounds were used to prepare anion-exchange membranes(AEMs) and an ionomer binder solution. The properties of the AEMs were investigated such as $OH^-$ conductivity, water content and dimension stability. Chloromethylation and amination of PSf were optimized in terms of the properties. Membrane-electrode assemblies were fabricated using anion-exchange membranes and the ionomer binder for solid alkaline fuel cells and direct borohydride fuel cells.

• Advances in Energy Research
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• v.2 no.1
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• pp.21-31
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• 2014

The use of a microporous membrane along with Au/C catalyst for direct glycerol alkaline fuel cell was investigated. In comparison with Nafion 112, the microporous Celgard 3401 membrane provides a better cell performance due to the lower ionic resistance as confirmed by impedance spectra. The single cell using Au/C as anode catalyst prepared by using PVA protection techniques provided a higher maximum power density than the single cell with commercial PtRu/C at $18.65mW\;cm^{-2}$ The short-term current decay studies show a better stability of Au/C single cell. The higher activity of Au/C over PtRu/C was owing to the lower activation loss of Awe. The magnitude of current decay indicates a low problem of glycerol crossover from anode to cathode side. The similar performance of single cell with and without humudification at cathode points out an adequate transport of water through the microporous membrane.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.691-695
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• 2017

Optimization study was carried out to improve the durability of the gas diffusion layer (GDL) in alkaline fuel cell cathode by the use of highly stable PDMS superhydrophobic coating. Two different commercial GDLs were selected as substrates. Coating temperature and viscosity of PDMS were controlled for the stability of structure in microporous layer of GDL as well as uniform coating according to thermal characteristics of GDL. Regardless of PDMS viscosity, highly stable superhydrophobicities were obtained with both GDLs at $200^{\circ}C$. After the accelerated test, however, 28BC GDL coated with 1000 CS PDMS showed the best durability with the lowest loss of superhydrophobicity.

• Journal of Electrochemical Science and Technology
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• v.8 no.3
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• pp.183-196
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• 2017

The research efforts directed at advancing water electrolysis technology continue to intensify together with the increasing interest in hydrogen as an alternative source of energy to fossil fuels. Among the various water electrolysis systems reported to date, systems employing a solid polymer electrolyte membrane are known to display both improved safety and efficiency as a result of enhanced separation of products: hydrogen and oxygen. Conducting water electrolysis in an alkaline medium lowers the system cost by allowing non-platinum group metals to be used as catalysts for the complex multi-electron transfer reactions involved in water electrolysis, namely the hydrogen and oxygen evolution reactions (HER and OER, respectively). We briefly review the anion exchange membranes (AEMs) and electrocatalysts developed and applied thus far in alkaline AEM water electrolysis (AEMWE) devices. Testing the developed components in AEMWE cells is a key step in maximizing the device performance since cell performance depends strongly on the structure of the electrodes containing the HER and OER catalysts and the polymer membrane under specific cell operating conditions. In this review, we discuss the properties of reported AEMs that have been used to fabricate membrane-electrode assemblies for AEMWE cells, including membranes based on polysulfone, poly(2,6-dimethyl-p-phylene) oxide, polybenzimidazole, and inorganic composite materials. The activities and stabilities of tertiary metal oxides, metal carbon composites, and ultra-low Pt-loading electrodes toward OER and HER in AEMWE cells are also described.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.19-27
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• 2022

A series of QPAE/TiO₂-x (x = 1, 4, 7 and 10 wt%) organic/inorganic composite membranes were prepared as electrolyte membranes for alkaline anion exchange membrane fuel cells by controlling the content of inorganic filler with quaternized poly(arylene ether) (QPAE) random copolymer. Among the prepared QPAE/TiO₂-x organic/inorganic composite membranes, the highest ionic conductivity was 26.6 mS cm^-1 at 30℃ in QPAE/TiO₂-7 composite membrane, which was improvement over the ionic conductivity value of 6.4 mS cm^-1 (at 30℃) of the pristine QPAE membrane. Furthermore, the water uptake, swelling ratio, ionic exchange capacity, and thermal property of QPAE/TiO₂-x composite membranes were improved compared to the pristine QPAE membrane. The results of these studies suggest that the fabricated QPAE/TiO₂-x composite membranes have good prospects for alkaline anion exchange membrane fuel cell applications.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.652-658
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• 2019

Direct hydrazine fuel cells (DHFCs) have been considered to be one of the promising fuel cells because hydrazine as a liquid fuel possesses several advantages such as no emission of CO₂, relatively high energy density and catalytic activity over platinum group metal (PGM)-free anode catalysts. Judging from plenty of research works, however, regarding key components such as electrocatalysts as well as their physicochemical properties, it becomes quite necessary to understand better the underlying processes in DHFCs for the long term stability. Herein, we highlight recent studies of DHFCs in terms of a systematic approach for developing cost-effective and stable anode catalysts and electrode structures that incorporate mass transport characteristics of hydrazine, water and gas bubbles.

• Journal of the Korean Electrochemical Society
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• v.19 no.3
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• pp.107-113
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• 2016

In this study, an anion-exchange ionomer solution was prepared by grinding poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) in liquid nitrogen for solid alkaline fuel cells (SAFCs). Type of quaternized PPO (QPPO) solutions was controlled by grinding time. The ionomer binder solutions were characterized in terms of dispersity, particle size, and electrochemical properties. As a result, ionomer binder solutions using grinded polymer showed higher dispersion and smaller particle size distribution than that using non-grinded polymer. The highest ionic conductivity and IEC of the membrane recast by using BPPO-G120s were $0.025S\;cm^{-1}$ and $1.26meq\;g^{-1}$, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.5
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• pp.458-465
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• 2018

This study reports the fabrication of anion exchange membranes (AEMs) containing two kinds of functional groups: i) trimethylphosphite (TMP) and ii) trimethylamine (TMA). We carried out the synthesis of polymers to enhance thermal stability and ion conductivity. The alternative polymer was prepared using 2,2-bis(4-hydroxy-3-methylphenyl)propane and decafluorobiphenyl. The membrane was fabricated by solution casting method. The thermal stability of membranes was examined by TGA. The physiochemical properties of membranes were also investigated in terms of water uptake, swelling ratio, ion exchange capacity, and ion conductivity. The hydroxide ion conductivity of the membranes reached about 20.2 mS/cm for quaternary ammonium poly(arylene ether) (QA-PAE) containing TMA moiety and 5.1 mS/cm for quaternary phosphonium PAE (QP-PAE) containing TMP moiety at $90^{\circ}C$.