Controlling fuel crossover and hydration in ultra-thin proton exchange membrane-based fuel cells using Pt-nanosheet catalysts

2014 ◽  
Vol 2 (39) ◽  
pp. 16416-16423 ◽  
Author(s):  
Rujie Wang ◽  
Wenjing Zhang ◽  
Gaohong He ◽  
Ping Gao

A fuel cell with a 9 μm thick proton exchange membrane bearing Pt-nanosheet catalysts delivered 200% more power density as compared with a fuel cell with commercial Nafion® 211 membrane.

2005 ◽  
Vol 2 (2) ◽  
pp. 121-135 ◽  
Author(s):  
A. Mawardi ◽  
F. Yang ◽  
R. Pitchumani

The performance of fuel cells can be significantly improved by using optimum operating conditions that maximize the power density subject to constraints. Despite its significance, relatively scant work is reported in the open literature on the model-assisted optimization of fuel cells. In this paper, a methodology for model-based optimization is presented by considering a one-dimensional nonisothermal description of a fuel cell operating on reformate feed. The numerical model is coupled with a continuous search simulated annealing optimization scheme to determine the optimum solutions for selected process constraints. Optimization results are presented over a range of fuel cell design parameters to assess the effects of membrane thickness, electrode thickness, constraint values, and CO concentration on the optimum operating conditions.


Author(s):  
Sreedhar Kari ◽  
George Thorne ◽  
John Szeki ◽  
Chris Hall ◽  
Lindsey Mortimer ◽  
...  

Abstract Increased greenhouse gas emissions have an adverse impact on climate change. Recently, there is an increased drive to reduce the emissions especially after the Paris agreement 2015. There are several research initiatives that have been started in the aerospace industry to reduce the emissions like NOx, CO2 and other harmful substances. This paper presents the case studies done on the potential applications of fuel cells for more electric aircrafts (MEA) to achieve the reduced emissions and reduced fuel consumption. The objective of this paper is to take a broad view of how fuel cell technology works, various types of existing technologies and their potential applications and challenges for aero engines in terms of power density. In this study, the different types of fuel cells e.g. low temperature Proton Exchange Membrane (PEM) fuel cells and high temperature solid oxide fuel cells (SOFC) etc were studied and identified the opportunities and challenges to make them work for aero engines as a part of electrification. Different ways of storing the hydrogen on board have been explored. The comparison has been made with battery vs fuel cell power density including the H2 tank. The case studies were made for potential replacement of shaft power off take on civil large engines with fuel cells for hybrid long range aircrafts and regional propeller jets with fully electric power.


Author(s):  
Haojie Wang ◽  
Ruiqing Wang ◽  
Sheng Sui ◽  
Tai Sun ◽  
Yichang Yan ◽  
...  

AbstractAn advanced cathode design can improve the power performance and durability of proton exchange membrane fuel cells (PEMFCs), thus reducing the stack cost of fuel cell vehicles (FCVs). Recent studies on highly active Pt alloy catalysts, short-side-chain polyfluorinated sulfonic acid (PFSA) ionomer and 3D-ordered electrodes have imparted PEMFCs with boosted power density. To achieve the compacted stack target of 6 kW/L or above for the wide commercialization of FCVs, developing available cathodes for high-power-density operation is critical for the PEMFC. However, current developments still remain extremely challenging with respect to highly active and stable catalysts in practical operation, controlled distribution of ionomer on the catalyst surface for reducing catalyst poisoning and oxygen penetration losses and 3D (three-dimensional)-ordered catalyst layers with low Knudsen diffusion losses of oxygen molecular. This review paper focuses on impacts of the cathode development on automotive fuel cell systems and concludes design directions to provide the greatest benefit.


2019 ◽  
Author(s):  
Valentina Guccini ◽  
Annika Carlson ◽  
Shun Yu ◽  
Göran Lindbergh ◽  
Rakel Wreland Lindström ◽  
...  

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g<sup>-1</sup>), counterion (H<sup>+</sup>or Na<sup>+</sup>), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH as measured by Small Angle X-ray scattering shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na<sup>+</sup>or H<sup>+</sup>). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm<sup>-1</sup>at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.<br>


2017 ◽  
Vol 10 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Mohammed Jourdani ◽  
Hamid Mounir ◽  
Abdellatif El Marjani

Background: During last few years, the proton exchange membrane fuel cells (PEMFCs) underwent a huge development. Method: The different contributions to the design, the material of all components and the efficiencies are analyzed. Result: Many technical advances are introduced to increase the PEMFC fuel cell efficiency and lifetime for transportation, stationary and portable utilization. Conclusion: By the last years, the total cost of this system is decreasing. However, the remaining challenges that need to be overcome mean that it will be several years before full commercialization can take place.This paper gives an overview of the recent advancements in the development of Proton Exchange Membrane Fuel cells and remaining challenges of PEMFC.


2015 ◽  
Vol 3 (16) ◽  
pp. 8847-8854 ◽  
Author(s):  
Zhibin Guo ◽  
Ruijie Xiu ◽  
Shanfu Lu ◽  
Xin Xu ◽  
Shichun Yang ◽  
...  

A novel submicro-pore containing proton exchange membrane is designed and fabricated for application in high-temperature fuel cells.


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):  
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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