Composition and performance modelling of catalyst layer in a proton exchange membrane fuel cell

1999 ◽  
Vol 77 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Curtis Marr ◽  
Xianguo Li
Author(s):  
Curtis Marr ◽  
Xianguo Li

The composition and performance optimisation of cathode catalyst platinum and catalyst layer structure in a proton exchange membrane fuel cell has been investigated by including both electrochemical reaction and mass transport process. It is found that electrochemical reactions occur in a thin layer within a few micrometers thick, indicating ineffective catalyst utilization for the present catalyst layer design. The effective use of platinum catalyst decreases with increasing current density, hence lower loadings of platinum are feasible for higher current densities of practical interest without adverse effect on cell performance. The optimal void fraction for the catalyst layer is about 60% and fairly independent of current density, and a 40% supported platinum catalyst yields the best performance amongst various supported catalysts investigated. An optimal amount of membrane content in the void region of the catalyst layer exists for minimum cathode voltage losses due to competition between proton migration through the membrane and oxygen transfer in the void region. The present results will be useful for practical fuel cell designs.


2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.


Author(s):  
N. Akhtar ◽  
P. J. A. M. Kerkhof

The role of gas diffusion media with differently structured properties have been examined with emphasis on the liquid water saturation within the cathode of a proton exchange membrane fuel cell (PEMFC). The cathode electrode consists of a gas diffusion layer (GDL), a micro-porous layer and a catalyst layer (CL). The liquid water saturation profiles have been calculated for varying structural and physical properties, i.e., porosity, permeability, thickness and contact angle for each of these layers. It has been observed that each layer has its own role in determining the liquid water saturation within the CL. Among all the layers, the GDL is the most influential layer that governs the transport phenomena within the PEMFC cathode. Besides, the thickness of the CL also affects the liquid water saturation and it should be carefully controlled.


Author(s):  
Utku Gulan ◽  
Hasmet Turkoglu ◽  
Irfan Ar

In this study, the fluid flow and cell performance in cathode side of a proton exchange membrane (PEM) fuel cell were numerically analyzed. The problem domain consists of cathode gas channel, cathode gas diffusion layer, and cathode catalyst layer. The equations governing the motion of air, concentration of oxygen, and electrochemical reactions were numerically solved. A computer program was developed based on control volume method and SIMPLE algorithm. The mathematical model and program developed were tested by comparing the results of numerical simulations with the results from literature. Simulations were performed for different values of inlet Reynolds number and inlet oxygen mole fraction at different operation temperatures. Using the results of these simulations, the effects of these parameters on the flow, oxygen concentration distribution, current density and power density were analyzed. The simulations showed that the oxygen concentration in the catalyst layer increases with increasing Reynolds number and hence the current density and power density of the PEM fuel cell also increases. Analysis of the data obtained from simulations also shows that current density and power density of the PEM fuel cell increases with increasing operation temperature. It is also observed that increasing the inlet oxygen mole fraction increases the current density and power density.


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