• 한국전기화학회:학술대회논문집
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• 2002.10a
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• pp.8-8
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• 2002

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.778-782
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• 2012

Until a recent day, degradation of PEMFC MEA (membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. Therefore in this work, AST (Accelerated Stress Test) of MEA degradation was done at the condition that membrane and electrode were degraded simultaneously. There was interaction between membrane degradation and electrode degradation. Membrane degradation reduced the decrease range of catalyst active area by electrode degradation. Electrode degradation reduces increase range of the hydrogen crossover current and FER (Fluoride Emission Rate) by membrane degradation.

• Clean Technology
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• v.19 no.1
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• pp.59-64
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• 2013

Pt/carbon Electrode catalysts for PEMFC were synthesized using colloidal method. PSA (platinum sulfite acid) was used as a Pt precursor and CPA (chloroplatinic acid) was also used to replace relatively expensive PSA. Electrode catalysts prepared using PSA showed Pt particle size less than 3.5 nm and Pt yield higher than 90% in 10~40 wt% Pt loading. Electrode catalysts prepared using CPA also showed Pt particle size less than 4.4 nm and Pt yield higher than 80% in 10~40 wt% Pt loading. The MEA (membrane electrode assembly) using 20 wt% Pt/VXC72 showed equivalent I-V curve comparing with commercial electrode catalyst in single cell test.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.68-72
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• 2013

Until a recent day, degradation of PEMFC MEA (membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. During simultaneous degradation, there was interaction between membrane degradation and electrode degradation. The effect of electrode degradation on membrane degradation was studied in this work. We compared membrane degradation after electrode degradation and membrane degradation without electrode degradation. I-V performance, hydrogen crossover current, fluoride emission rate (FER), impedance and TEM were measured after and before degradation of MEA. Electrode degradation reduced active area of Pt catalyst, and then radical/$H_2O_2$ evolution rate decreased on Pt. Decrease of radical/$H_2O_2$ reduced the velocity of membrane degradation.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.43-48
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• 2002

In this study, high performance electrode catalyst was developed in fabrication of membrane electrode assembly for PEMFCs(Polymer Electrolyte Membrane Fuel Cells). The I-V characteristics were measured to evaluate the influence of Nafion solution and Pt loading amount in the catalyst composition. The electrode characteristics were also investigated with respect to temperature change. The electrode performance was optimized at Nafion 5 wt% and 0.5 mg Pt/$\textrm{cm}^2$ content. The increase in the concentration of Nafion solution resulted in the decrease in electrode performance. At $80^{\circ}C$ of unit cell, I-V characteristics excelled those obtained at lower temperature. There was no difference in performance at low current density, but the improvement of voltage value in higher temperature could be found at high current density.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.93-96
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• 2007

Recently, much attentions have been paid on the commercialization of PEMFC, especially for the applications of residential and portable. In order to achieve the early commercialization of PEMFC, thee are two hurdles to overcome. One is cost down and the other is improvement of durability of the system components. Numerous companies have tried to reduce the production cost and the main research topics have been changed from performance to durability improvement. In this work, acceleration test were performed to find and evaluate the main reason of degradation of the MEA(membrane-electrode assembly) which is one of the core component of the PEMFC system. Based upon the test results, a way to make durable MEA was suggested. Acceleration tests were made by applying high voltage of 1.2V to the several kinds of single cells to increase the growth of catalyst particles. Cell performance, ac-impedance and electrochemically active area measurements were made atfter every 8 hours of acceleration test. Degradations of catalyst and membrane were examined by SEM, TEM and XRD. Obtained results were discussed in terms of structural stability and loss of catalyt and ionomers in the electrode layer. In addition, the way to make highly durable MEA was suggested.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.425-429
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• 2014

Until a recent day, degradation of PEMFC MEA(membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. During simultaneous degradation, there was interaction between membrane degradation and electrode degradation. Hydrogen permeability was used often to measure degradation of electrolyte membrane in PEMFC. In case of hydrogen permeability measured by LSV(Linear Sweep Voltammetry) method, the degradation of electrode decrease the value of hydrogen crossover current due to LSV methode's dependence on electrode active area. In this study hydrogen permeability was measured by gas chromatograph(GC) when membrane and electrode degraded at the same time. It was showed that degradation of electrode did not affect the hydrogen permeability measured by GC because of GC methode's independence on electrode active area.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.6
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• pp.547-553
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• 2015

For commercialization of fuel cell electric vehicles, one of the key objectives is to reduce cost of full stack assembly. Regarding Membrane Electrode Assembly, the major issue is to improve fuel cell activation process in the initial Hydrogen Oxidation Reaction and Oxygen Reduction Reaction. In this research, the VD (Vacuum Drying) process has been developed for improvement of activation process. The VD condition is developed by controlling the temperature and degree of vacuum to remove the remaining solvent of electrode. Consequently, the electrode applied to VD process showed the low characteristics such as 3.5% of remaining solvent content and the improved efficiency such as 15% of activation process speed.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.137-143
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• 2021

As an electrochemical water electrolysis for green hydrogen production, both polymer electrolyte membrane (PEM) and alkaline electrolyte are being developed extensively in various countries. The PEM electrolyzer with high current density (above 2 A/cm²) has the advantage of being able to design a simple structure. Also, it is known that it has high response to electrical output fluctuations. However, the cost problem of major components is the most important issue that a PEM electrolyzer must overcome. Instantly, there are platinum group metal (PGM)-based electrocatalysts, fluorine-based polyfluoro sulfuric acid (PFSA) membrane, Ti felt (porous transport layer, PTL) and so on. Another challenging issue is productivity. A securing outstanding productivity brings price benefits of the electrolytic cells. From this point of view, we conducted basic studies on manufacturing electrode and membrane electrode assembly (MEA) for PEM electrolyzer production.

• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.27-30
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• 2003

The effect of fabrication method of catalytic layer on electrode performance has been investigated. Brush, spray gun and screen printer were used as fabrication tool and catalytic layers were formed by several methods in screen printing. Direct screen printing on polymer membrane, screen printing on carbon paper, and their combined method were applied. In the electrode fabricated by the screen printing method, Pt loading of Pt/C catalysts could be cut down to 50%, compared with results by the brushing and spraying methods. The best result of electrode was obtained as 0.6 V, at 1 A/$\textrm{cm}^2$ when catalytic layer was formed by the combined way.