The Experts below are selected from a list of 10896 Experts worldwide ranked by ideXlab platform
Shoucheng He - One of the best experts on this subject based on the ideXlab platform.
-
improving solid oxide Fuel Cell Performance by a single step co firing process
Journal of Power Sources, 2015Co-Authors: Han Chen, Shoucheng HeAbstract:Abstract Solid oxide Fuel Cells (SOFCs) with Sm 0.2 Ce 0.8 O 2-δ (SDC) as the electrolyte are successfully prepared by a single-step co-firing process with the sintering temperature as low as 1100 °C. Different from the conventional SOFC preparation procedure that involves multistep firing processes, the single-step co-firing preparation procedure simplifies the Fuel Cell preparation procedure and additionally improves the Fuel Cell Performance. The Cell prepared by the single-step process exhibits the maximum power density of 289 mW cm −2 at 700 °C, while the Cell prepared by the conventional method is only 211 mW cm −2 , with an increase of 37% been achieved. The impedance analysis reveals that the single co-firing procedure not only improves the contact between the electrolyte and electrodes, but also lowers the Cell polarization resistance, thus leading to a better Fuel Cell Performance.
Leon T Yu - One of the best experts on this subject based on the ideXlab platform.
-
influence of the composition of isopropyl alcohol water mixture solvents in catalyst ink solutions on proton exchange membrane Fuel Cell Performance
Journal of Power Sources, 2013Co-Authors: Leon T YuAbstract:Abstract We study the morphology of Nafion in the dilute IPA (isopropyl alcohol)/water mixture solutions containing 20–100 wt.% of IPA and in the Pt–C/Nafion gas diffusion electrodes (GDEs; where Pt–C is the carbon powder deposited on its surface with Pt particles), which are prepared by spraying on the carbon paper surfaces with a layer of Pt–C, Nafion and IPA/water ink solution. The Fuel Cell Performance of the GDEs strongly depends on the Nafion morphology in the ink solutions. A lower IPA content in the Pt–C/Nafion ink solutions results in the formation of larger and higher negatively charged Nafion aggregated particles, which leads to higher steric hindrance of the deposition of Nafion ionomer on the surface of Pt–C particles and thus a thinner Nafion film in contact on the Pt–C particle surfaces. The thinner Nafion film in contact with the Pt particles in the CL increases the chances of the Pt particles in contact with the H 2 /O 2 gas, leading to a higher Fuel Cell Performance.
Han Chen - One of the best experts on this subject based on the ideXlab platform.
-
improving solid oxide Fuel Cell Performance by a single step co firing process
Journal of Power Sources, 2015Co-Authors: Han Chen, Shoucheng HeAbstract:Abstract Solid oxide Fuel Cells (SOFCs) with Sm 0.2 Ce 0.8 O 2-δ (SDC) as the electrolyte are successfully prepared by a single-step co-firing process with the sintering temperature as low as 1100 °C. Different from the conventional SOFC preparation procedure that involves multistep firing processes, the single-step co-firing preparation procedure simplifies the Fuel Cell preparation procedure and additionally improves the Fuel Cell Performance. The Cell prepared by the single-step process exhibits the maximum power density of 289 mW cm −2 at 700 °C, while the Cell prepared by the conventional method is only 211 mW cm −2 , with an increase of 37% been achieved. The impedance analysis reveals that the single co-firing procedure not only improves the contact between the electrolyte and electrodes, but also lowers the Cell polarization resistance, thus leading to a better Fuel Cell Performance.
Mahrokh Samavati - One of the best experts on this subject based on the ideXlab platform.
-
study of pem Fuel Cell Performance by electrochemical impedance spectroscopy
International Journal of Hydrogen Energy, 2010Co-Authors: Saeed Asghari, Ali Mokmeli, Mahrokh SamavatiAbstract:Electrochemical impedance spectroscopy is a suitable and powerful diagnostic testing method for Fuel Cells because it is non-destructive and provides useful information about Fuel Cell Performance and its components. This paper presents the diagnostic testing results of a 120 W single Cell and a 480 W PEM Fuel Cell short stack by electrochemical impedance spectroscopy. The effects of clamping torque, non-uniform assembly pressure and operating temperature on the single Cell impedance spectrum were studied. Optimal clamping torque of the single Cell was determined by inspection of variations of high frequency and mass transport resistances with the clamping torque. The results of the electrochemical impedance analysis show that the non-uniform assembly pressure can deteriorate the Fuel Cell Performance by increasing the ohmic resistance and the mass transport limitation. Break-in procedure of the short stack was monitored and it is indicated that the ohmic resistance as well as the charge transfer resistance decrease to specified values as the break-in process proceeds. The effect of output current on the impedance plots of the short stack was also investigated.
-
Study of PEM Fuel Cell Performance by electrochemical impedance spectroscopy
International Journal of Hydrogen Energy, 2010Co-Authors: Saeed Asghari, Ali Mokmeli, Mahrokh SamavatiAbstract:Electrochemical impedance spectroscopy is a suitable and powerful diagnostic testing method for Fuel Cells because it is non-destructive and provides useful information about Fuel Cell Performance and its components. This paper presents the diagnostic testing results of a 120 W single Cell and a 480 W PEM Fuel Cell short stack by electrochemical impedance spectroscopy. The effects of clamping torque, non-uniform assembly pressure and operating temperature on the single Cell impedance spectrum were studied. Optimal clamping torque of the single Cell was determined by inspection of variations of high frequency and mass transport resistances with the clamping torque. The results of the electrochemical impedance analysis show that the non-uniform assembly pressure can deteriorate the Fuel Cell Performance by increasing the ohmic resistance and the mass transport limitation. Break-in procedure of the short stack was monitored and it is indicated that the ohmic resistance as well as the charge transfer resistance decrease to specified values as the break-in process proceeds. The effect of output current on the impedance plots of the short stack was also investigated. © 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.
Esmaiel Saievar-iranizad - One of the best experts on this subject based on the ideXlab platform.
-
The effects of porosity distribution variation on PEM Fuel Cell Performance
Renewable Energy, 2005Co-Authors: Ramin Roshandel, Bijan Farhanieh, Esmaiel Saievar-iranizadAbstract:Gas diffusion layers (GDL) are one of the important parts of the PEM Fuel Cell as they serve to transport the reactant gases to the catalyst layer. Porosity of this layer has a large effect on the PEM Fuel Cell Performance. The spatial variation in porosity arises due to two effects: (1) compression of the electrode on the solid landing areas and (2) water produced at the cathode side of gas diffusion layers. Both of these factors change the porosity of gas diffusion layers and affect the Fuel Cell Performance. To implement this Performance analysis, a mathematical model which considers oxygen and hydrogen mass fraction in gas diffusion layer and the electrical current density in the catalyst layer, and the Fuel Cell potentials are investigated. The porosity variation in the GDL is calculated by considering the applied pressure and the amount of the water generated in the Cell. The validity of the model is approved by comparing the computed results with experimental data. The obtained results show that the decrease in the average porosity causes the reduction in oxygen consumption, so that a lower electrical current density is generated. It is also shown that when the electrical current density is low, the porosity variation in gas diffusion layer has no significant influence on the level of polarization whereas at higher current density the influence is very significant. The porosity variation causes non-uniformity in the mass transport which in turn reduces the current density and a lower Fuel Cell Performance is obtained.
-
The Effects of Porosity Distribution Variation in GDL on PEM Fuel Cell Performance
2nd International Conference on Fuel Cell Science Engineering and Technology, 2004Co-Authors: Ramin Roshandel, Bijan Farhanieh, Esmaiel Saievar-iranizadAbstract:Gas diffusion layers are one of the important parts of the PEM Fuel Cell as they serve to transport to transport the reactant gases to the catalyst layer. Porosity of this layer has a large effect on the PEM Fuel Cell Performance. The spatial variation in porosity arises due to two effects: 1. Compression of the electrode on the solid landing areas and 2. Water produced at the cathode side of gas diffusion layers. Both of these factors change the porosity of gas diffusion layers affects Fuel Cell Performance. To implement this Performance analysis, a mathematical model which considers oxygen and hydrogen mass fraction in gas diffusion layer and the electrical current density in the catalyst layer, and the Fuel Cell potentials is investigated. The porosity variation in the GDL is calculated by considering the applied pressure and the amount of the water generated in the Cell. The validity of the model is assessed by comparing the computed results with experimental data. The obtained results show that the decrease in the average porosity causes the reduction in oxygen consumption, so that a lower electrical current density is generated. It is also shown that when the electrical current density is low, the porosity variation in gas diffusion layer has no significant influence on the level of polarization whereas at higher current density the influence is very significant. The porosity variation causes non-uniformity in the mass transport which in turn reduces the current density and a lower Fuel Cell Performance is obtained.Copyright © 2004 by ASME
