scholarly journals Optimization of Membrane Electrode Assembly of PEM Fuel Cell by Response Surface Method

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3097 ◽  
Author(s):  
Vuppala ◽  
Chedir ◽  
Jiang ◽  
Chen ◽  
Aziz ◽  
...  

The membrane electrode assembly (MEA) plays an important role in the proton exchange membrane fuel cell (PEMFC) performance. Typically, the structure comprises of a polymer electrolyte membrane sandwiched by agglomerate catalyst layers at the anode and cathode. Optimization of various parameters in the design of MEA is, thus, essential for reducing cost and material usage, while improving cell performance. In this paper, optimization of MEA is performed using a validated two-phase PEMFC numerical model. Key MEA parameters affecting the performance of a single PEMFC are determined from sensitivity analysis and are optimized using the response surface method (RSM). The optimization is carried out at two different operating voltages. The results show that membrane thickness and membrane protonic conductivity coefficient are the most significant parameters influencing cell performance. Notably, at higher voltage (0.8 V per cell), the current density can be improved by up to 40% while, at a lower voltage (0.6 V per cell), the current density may be doubled. The results presented can be of importance for fuel cell engineers to improve the stack performance and expedite the commercialization.

2013 ◽  
Vol 38 (22) ◽  
pp. 9484-9493 ◽  
Author(s):  
U.A. Hasran ◽  
S.K. Kamarudin ◽  
W.R.W. Daud ◽  
B.Y. Majlis ◽  
A.B. Mohamad ◽  
...  

Author(s):  
C. C. Kuo ◽  
W. E. Lear ◽  
J. H. Fletcher ◽  
O. D. Crisalle

A constructive critique and a suite of proposed improvements for a recent one-dimensional semianalytical model of a direct methanol fuel cell are presented for the purpose of improving the predictive ability of the modeling approach. The model produces a polarization curve for a fuel cell system comprised of a single membrane-electrode assembly, based on a semianalytical one-dimensional solution of the steady-state methanol concentration profile across relevant layers of the membrane electrode assembly. The first improvement proposed is a more precise numerical solution method for an implicit equation that describes the overall current density, leading to better convergence properties. A second improvement is a new technique for identifying the maximum achievable current density, an important piece of information necessary to avoid divergence of the implicit-equation solver. Third, a modeling improvement is introduced through the adoption of a linear ion-conductivity model that enhances the ability to better match experimental polarization-curve data at high current densities. Fourth, a systematic method is advanced for extracting anodic and cathodic transfer-coefficient parameters from experimental data via a least-squares regression procedure, eliminating a potentially significant parameter estimation error. Finally, this study determines that the methanol concentration boundary condition imposed on the membrane side of the membrane-cathode interface plays a critical role in the model’s ability to predict the limiting current density. Furthermore, the study argues for the need to carry out additional experimental work to identify more meaningful boundary concentration values realized by the cell.


Author(s):  
Tzyy-Lung Leon Yu ◽  
Shih-Hao Liu ◽  
Hsiu-Li Lin ◽  
Po-Hao Su

The PBI (poly(benzimidazole)) nano-fiber thin film with thickness of 18–30 μm is prepared by electro-spinning from a 20 wt% PBI/DMAc (N, N′-dimethyl acetamide) solution. The PBI nano-fiber thin film is then treated with a glutaraldehyde liquid for 24h at room temperature to proceed chemical crosslink reaction. The crosslink PBI nano-fiber thin film is then immersed in Nafion solutions to prepare Nafion/PBI nano-fiber composite membranes (thickness 22–34 μm). The morphology of the composite membranes is observed using a scanning electron microscope (SEM). The mechanical properties, conductivity, and unit fuel cell performance of membrane electrode assembly (MEA) of the composite membrane are investigated and compared with those of Nafion-212 membrane (thickness ∼50 μm) and Nafion/porous PTFE (poly(tetrafluoro ethylene)) composite membrane (thickness ∼22 μm). We show the present composite membrane has a similar fuel cell performance to Nafion/PTFE and a better fuel cell performance than Du Pont Nafion-212.


2018 ◽  
Vol 778 ◽  
pp. 275-282
Author(s):  
Noaman Khan ◽  
Saim Saher ◽  
Xuan Shi ◽  
Muhammad Noman ◽  
Mujahid Wasim Durani ◽  
...  

Highly porous ZIF-67 (Zeolitic imidazole framework) has a conductive crystalline metal organic framework (MOF) structure which was served as a precursor and template for the preparation of nitrogen-doped carbon nanotubes (NCNTs) electrocatalysts. As a first step, the chloroplatinic acid, a platinum (Pt) precursor was infiltrated in ZIF-67 with a precise amount to obtain 0.12 mg.cm-2 Pt loading. Later, the infiltrated structure was calcined at 700°C in Ar:H2 (90:10 vol%) gas mixture. Multi-walled nitrogen-doped carbon nanotubes were grown on the surface of ZIF-67 crystals following thermal activation at 700°C. The resulting PtCo-NCNTs electrocatalysts were deposited on Nafion-212 solid electrolyte membrane by spray technique to study the oxygen reduction reaction (ORR) in the presence of H2/O2 gases in a temperature range of 50-70°C. The present study elucidates the performance of nitrogen-doped carbon nanotubes ORR electrocatalysts derived from ZIF-67 and the effects of membrane electrode assembly (MEA) steaming on the performance of proton exchange membrane fuel cell (PEMFC) employing PtCo-NCNTs as ORR electrocatalysts. We observed that the peak power density at 70°C was 450 mW/cm2 for steamed membrane electrode assembly (MEA) compared to 392 mW/cm2 for an identical MEA without steaming.


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