• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2014.11a
• /
• pp.274-274
• /
• 2014

• 한국전기화학회:학술대회논문집
• /
• 2003.07a
• /
• pp.239-242
• /
• 2003

• Transactions of the Korean hydrogen and new energy society
• /
• v.22 no.1
• /
• pp.42-50
• /
• 2011

The Montmorillonite (MMT) in the polymer matrix is expected to reduce methanol permeability due to the tortous path formed by dispersed silicate layers. However, the polymer composite membranes containing non-proton conducting inorganic particle tend to show low proton conductivity. To solve this problem, we used an ion exchange method to prepare functionalized MMT with various silane coupling agents. The modified MMT was randomly dispersed in sulfonated poly (arylene ether sulfone) (SPAES) matrix to prepare SPAES/modified MMT composite membranes. The performances of hybrid membranes for DMFCs application were investigated. The SPAES/modified composite membrane showed increased proton conductivity compared with the non-modified MMT composite membrane. However, the methanol permeability of the SPAES/modified membrane was higher than that of the non-modified MMT.

• Korean Chemical Engineering Research
• /
• v.58 no.2
• /
• pp.171-175
• /
• 2020

In the proton exchange membrane fuel cells (PEMFC), the development of a reinforced membrane with improved durability by a support is actively in progress in Korea. In this study, the initial performance and characteristics of four types of reinforced membranes were compared. Reinforced membranes with higher amounts of C-F chains in the polymer membrane showed lower water diffusion coefficients due to the hydrophobicity of the C-F chains. The thicker the polymer membrane, the more the hydrogen permeability decreased and the higher the OCV. Membrane with short resistance below 1.5 Ωcm² showed OCV below 0.9 V and the lowest performance, so short resistance should be above 3.0 Ωcm². Compared with the current standard membrane, there was a similar domestic membrane, which could confirm the possibility of localization of PEMFC polymer membrane.

• Applied Chemistry for Engineering
• /
• v.19 no.2
• /
• pp.205-208
• /
• 2008

Sulfonated polySEBS and sulfonated PS were synthesized by sulfonation at the aromatic group of polySEBS and PS. Novel sulfonated polySEBS/sulfonated PS blending films for the ion exchange membrane of polymer electrolyte fuel cell were prepared from these sulfonated polymers. The proton conductivities of these blending films were varied in $10^{-2}{\sim}10^{-3}S/cm$ with the blending ratio of sulfonated polySEBS/sulfonated PS. Especially, the film prepared from the addition of the sulfonated PS (0.5 g) in the sulfonated polySEBS (10.0 g) has the best proton conductivity (0.07 S/cm) with ion exchange capacity (0.75 meq/g) and water uptake (25%).

• Journal of the Korean Solar Energy Society
• /
• v.34 no.4
• /
• pp.17-22
• /
• 2014

The design of a fuel cells stack is important to get optimal output power. This study focuses on the evaluation of fuel cell system for unmaned aerial vehicles (UAVs). Low temperature proton exchange membrane (LTPEM) fuel cells are the most promising energy source for the robot applications because of their unique advantages such as high energy density, cold startup, and quick response during operation. In this paper, a 600 W open cathode LTPEM fuel cell was tested to evaluate the performance and to determine optimal operating conditions. The open cathode design reduces the overall size of the system to meet the requirement for robotic application. The cruise power requirement of 600 W was supported entirely by the fuel cell while the additional power requirements during takeoff was extended using a battery. A peak of power of 900 W is possible for 10 mins with a lithium polymer (LiPo) battery. The system was evaluated under various load cycles as well as start-stop cycles. The system response from no load to full load meets the robot platform requirement. The total weigh of the stack was 2 kg, while the overall system, including the fuel processing system and battery, was 4 kg.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.3
• /
• pp.250-255
• /
• 2012

In this paper, the development and performance analysis of a fuel cell-powered unmanned aerial vehicle is described. A fuel cell system featuring 1 kW proton exchange membrane fuel cell combined with a highly pressurized fuel supply system is proposed. For the higher fuel consumption efficiency and simplification of overall system, dead-end type operation is chosen and each individual system such as purge system, fuel supply system, cooling system is developed. Considering that fluctuation of exterior load makes it hard to stabilize fuel cell performance, the power management system is designed using a fuel cell and lithium-ion battery hybrid system. After integration of individual system, the performance of unmanned aerial vehicle is analyzed using data from flight and laboratory test. In the result, overall system was properly operated but for more duration of flight, research on weight lighting and improvement of fuel efficiency is needed to be progressed.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.4
• /
• pp.323-329
• /
• 2012

A thermal management system of a proton exchange membrane fuel cell is taken charge of controlling the temperature of fuel cell stack by rejection of electrochemically reacted heat. Two major components of thermal management system are heat exchanger and pump which determines required amount of heat. Since the performance and durability of PEMFC system is sensitive to the operating temperature and temperature distribution inside the stack, it is necessary to control the thermal management system properly under guidance of operating strategy. The control study of the thermal management system is able to be boosted up with hardware in the loop simulation which directly connects the plant simulation with real hardware components. In this study, the plant simulation of fuel cell stack has been developed and the simulation model is connected with virtual data acquisition system. And HIL simulator has been developed to control the coolant supply system for the study of PEMFC thermal management system. The virtual data acquisition system and the HIL simulator are developed under LabVIEWTM Platform and the Simulation interface toolkit integrates the fuel cell plant simulator with the virtual DAQ display and HIL simulator.

• Transactions of the Korean hydrogen and new energy society
• /
• v.25 no.4
• /
• pp.378-385
• /
• 2014

In this research, we investigate electrical performance and electrochemical properties of graphene supported Pt (Pt/G) and PtM (M = Ni and Y) alloy catalysts (PtM/Gs) that are synthesized by modified polyol method. With the PtM/Gs that are adopted for oxygen reduction reaction (ORR) as cathode of proton exchange membrane fuel cells (PEMFCs), their catalytic activity and ORR performance and electrical performance are estimated and compared with one another. Their particle size, particle distribution and electrochemically active surface (EAS) area are measured by TEM and cyclic voltammetry (CV), respectively. On the other hand, regarding ORR activity and electrical performance of the catalysts, (i) linear sweeping voltammetry by rotating disk electrode and rotating ring-disk electrode and (ii) PEMFC single cell tests are used. The TEM and CV measurements demonstrate particle size and EAS of PtM/Gs are compatible with those of Pt/G. In case of PtNi/G, its half-wave potential, kinetic current density, transferred electron number per oxygen molecule and $H_2O_2$ production % are excellent. Based on data obtained by half-cell test, when PEMFC singlecell tests are carried out, current density measured at 0.6V and maximum power density of the PEMFC single cell employing PtNi/G are better than those employing Pt/G. Conclusively, PtNi/Gs synthesized by modified polyol shows better ORR catalytic activity and PEMFC performance than other catalysts.

• Korean Chemical Engineering Research
• /
• v.54 no.3
• /
• pp.305-309
• /
• 2016

Recently, there are many efforts focused on development of more economical non-fluorinated membranes for PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, to test the durability of sPEEK MEA (Membrane and Electrode Assembly), ADT (Accelerated Degradation Test) of MEA degradation was done at the condition that membrane and electrode were degraded simultaneously. Before and after degradation, I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance and charge transfer resistance were measured. Although the permeability of hydrogen through sPEEK membrane was low, sPEEK membrane was weaker to radical evolved at low humidity and OCV condition than fluorinated membrane such as Nafion. Performance after MEA degradation for 144 hours and 271 hours were reduced by 15% and 65%, respectively. It was showed that the main cause of rapid decrease of performance after 144 hours was shorting due to Pt/C particles in the pinholes.