• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.403.2-403.2
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• 2016

Porous materials play a significant role in energy storage and conversion applications such as catalyst support for polymer electrolyte membrane fuel cell. In particular, hierarchical porous materials with both micropores (poresize, ${\delta}$ < 2 nm) and regularly arranged mesopores (2 nm < ${\delta}$ < 50 nm) are known to greatly enhance the efficiency of catalytic reactions by providing enormous surface area as well as fast mass transport channels for both reactants and products from/to active sites. Although it is generally agreed that the microscopic structure of the porous materials directly affects the performance of these catalytic reactions, neither detailed mechanisms nor fundamental understanding are available at hand. In this study, we propose an atomistic model of hierarchical nanostructured porous carbons (HNPCs) in molecular dynamics simulations. By performing a systematic study, we found that structural features of the HNPC can be independently altered by tuning specific synthesis parameters, while remaining other structures unchanged. In addition, we show some structure-property relations including mechanical and gas transport properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.394-394
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• 2016

The oxygen reduction reaction (ORR) in a polymer electrolyte membrane (PEM) fuel cell requires the use of Pt-based catalysts. Due to the high cost and low abundance of Pt, many researchers have been studied to reduce the use of Pt while to enhance the catalytic performance of Pt. One of the promising strategies is the deposition of Pt as ultrathin skins of only a few atomic layers on nanoscale substrates made of another metal. This presentation will discuss the conformal deposition of Pt as uniform, ultrathin shells on Pd nanocrystals. By optimizing the catalytic behavior of Pt-based nanocrystals, we obtained the greatly enhanced ORR activity and durability.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.372-375
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• 2006

This paper proposes a parallel operation system of the Z-source active power filter using one fuel cells(FC) system. The proposed system is composed of two Z-source inverters operating in parallel only one PEM(Polymer Electrolyte Membrane)FC system. Also, as the control algorithm of the active power filter, a single phase P-Q theory and PI control are adopted. The effectiveness of the proposed the system is verified by the PSIM simulation in the steady state and the transient state.

• Carbon letters
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• v.14 no.2
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• pp.110-116
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• 2013

This study investigated a developed process for producing a composite bipolar plate having excellent conductivity by using coal tar pitch and phenol resin as binders. We used a pressing method to prepare a compact of graphite powder mixed with binders. Resistivity of the impregnated compact was observed as heat treatment temperature was increased. It was observed that pore sizes of the GCTP samples increased as the heat treatment temperature increased. There was not a great difference between the flexural strengths of GCTP-IM and CPR-IM as the heat treatment temperature was increased. The resistivity of GPR700-IM, heat treated at $700^{\circ}C$ using phenolic resin as a binder, was $4829{\mu}{\Omega}{\cdot}cm$ which was best value in this study. In addition, it is expected that with the appropriate selection of carbon powder and further optimization of process we can produce a composite bipolar plate which has excellent properties.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.143-148
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• 2002

SPE(solid polymer electrolyte) 수전해법은 고체고분자전해질 막(membrane)을 전해질로 사용하는 방법으로서 이 전해질 막은 알칼리 수전해에서의 KOH전해질과 격리막을 합쳐놓은 것과 같은 역할을 수행한다. SPE 수전해는 양극(anode)에서 촉매 전극에 의해 물로부터 산소기체(O$_2$)와 수소이온(H$^{+}$)이 발생되며 수소이온(H$^{+}$)은 다량의 물($H_2O$)분자와 함께 고체고분자전해질 막을 통하여 음극으로 이동하여 외부회로를 통해 도달한 전자(e)와 음극(cathode)에서 만나 수소기체(H$_2$)를 발생시키는 방법이다.(중략)

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.412-414
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• 2009

In recent times, starting up polymer electrolyte membrane fuel cells(PEMFC) in sub-zero condition is a great challenge of fuel cell electric vehicle(FCEV). The water produced in a cathode during PEMFCs operate. The water changes into the form of solid/ice in sub-zero temperatures and this makes trouble in PEMFC cells. Voltage of PEMFC drops and cold startup is failed. This paper describes an experimental study on the effect of thermal cycle to degradation of MEA in PEMFC.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.208-211
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• 2007

Polymer Electrolyte Membrane fuel cell(PEMFC)의 촉매로는 주로 carbon을 지지체로 사용한 Pt/C 흑은 Pt alloy/C을 사용하게 된다. 이때 PEMFC의 상용화에 있어 촉매의 안정성은 상용화 실현에 있어 중요한 요인으로 인식되고 있다. 촉매의 성능 저하는 Pt의 활성 면적(Active surface area)의 감소가 원인으로 얘기되어 지고 있으며 이는 지지체로 사용한 탄소에 나노 크기로 분산되어 있던 Pt 입자가 커지면서 활성 면적이 감소되어 지기 때문이다. 이번 연구에서는 상용 Pt/C를 사용하여 Cyclic Voltammetry(CV)의 장기간 운전 및 다양한 조건 변화를 통하여 Pt입자의 크기 증가에 미치는 요인에 대한 연구를 진행하였다. 이와 더불어 Linear Sweep Voltammety(LSV), TEM, 등을 통한 분석이 진행되었다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.563-567
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• 2009

The polymer electrolyte membrane fuel cell(PEMFC) with the advantages of low-operating temperature, high current density, low cost and volume, fast start-up ability, and suitability for discontinuous operation becomes the most reasonable and attractive power system for transportation vehicle and micro-grid power plant in a household. 200W PEM-type FCs system was integrated by this study, then the electrical characteristics and diagnosis of the fuel cell were analyzed with variations on mass flow rate and stack temperature. The ranges of the variations are 1~8L/min on $H_2$ volume and $20{\sim}70^{\circ}C$ on stack temperature.

• Environmental Engineering Research
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• v.13 no.4
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• pp.192-196
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• 2008

The generation of high purity hydrogen from reformed hydrocarbon fuels, or syngas, is essential for efficient operation of the fuel cell (PEMFC, Polymer Electrolyte Membrane Fuel Cell). Usually, major components of reformed gas are $H_2$, CO, $CO_2$ and $H_2O$. Especially a major component, CO poisons the electrode of fuel cells. The water gas shifter (WGS) that shifts CO to $CO_2$ and simultaneously produces $H_2$, was developed to a two stage catalytic conversion process involving a high temperature shifter (HTS) and a low temperature shifter (LTS). Also, experiments were carried out to reduce the carbon monoxide up to $3{\sim}4%$ in the HTS and lower than 5,000 ppm via the LTS.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.4
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• pp.291-297
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• 2003

As an alternative bipolar plate material for polymer electrolyte membrane fuel cell (PEMFC), TiN-coated 316 stainless was evaluated in terms of electrical contact resistance and water contact angle. Performance and lifetime of the TiN-coated 316 bipolar plates were measured in comparison with those of graphite and bare 316 bipolar plates. At a cell voltage of 0.6 V, current density of the single cells using graphite, AISI 316, and TiN/316 bipolar plates was 996, 796, and $896mA/cm^2$, respectively. By coating 316 stainless steel with TiN layer, performance degradation rate determined to be the voltage degradation rate at a cell voltage of 0.6 V was reduced from 2.3 to 0.43 mV/h.