Minimization of polarization resistance in solid oxide fuel cells by proper design of micro-/nano-structure of porous composite electrodes

2012 ◽  
Vol 61 ◽  
pp. 1-12 ◽  
Author(s):  
Siamak Farhad ◽  
Feridun Hamdullahpur
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Polarization Resistance ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Composite Electrodes ◽  
Porous Composite ◽  
Nano Structure ◽  
Proper Design

Effect of the Microstructure of Porous Composite Electrodes on the Electric Power Density of Solid Oxide Fuel Cells

2011 ◽  
Author(s):  
Siamak Farhad ◽  
Feridun Hamdullahpur
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Electric Power ◽  
Power Density ◽  
Average Power ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Composite Electrodes ◽  
Porous Composite ◽  
Macro Model

The electric power density generated in co-flow planar solid oxide fuel cells (SOFCs) with porous composite electrodes is predicted using the cell combined micro- macro-model; and the effect of the microstructural variables of the electrodes on the cell power generation is studied. In the combined micro- macro-model, the electrochemical performance of the porous composite electrodes is determined from the micro-model and the distributions of the temperature in solid structure of the cell and the temperature and species partial pressures of the bulk fuel and air streams are determined from the cell macro-model. As a case study, the effect of the microstructural variables of the porous composite electrodes of the Ni-YSZ/YSZ/LSM-YSZ cell operated at the given voltage, fuel utilization ratio, and excess air, on the average power density of the cell is investigated through computer simulation. The results reveal that there is an optimum value for each microstructural variables of the electrodes at which the cell power density is maximized.

Effects of Mass Transport on the Performance of Solid Oxide Fuel Cells Composite Electrodes

2006 ◽  
Vol 4 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Marco Cannarozzo ◽  
Simone Grosso ◽  
Gerry Agnew ◽  
Adriana Del Borghi ◽  
Paola Costamagna
Keyword(s):  
Fuel Cells ◽  
Mass Transport ◽  
Solid Oxide Fuel Cells ◽  
Gas Diffusion ◽  
Transport Equations ◽  
Solid Oxide ◽  
The Other ◽  
Oxide Fuel ◽  
Composite Electrodes ◽  
The Impact

Composite electrodes are of great interest in the field of solid oxide fuel cells because their use can improve the performance of these cells. However, an important correlation exists between composition, microstructure, and thickness of an electrode and its performance. This correlation has been investigated in this work using a theoretical model. The model, in order to consider all the losses occurring in an electrode, includes Ohm’s law for ionic and electronic charge transport, and the Butler-Volmer equation to evaluate the activation polarizations, and mass transport equations, taking into account diffusion through porous media, to evaluate the concentration losses. The model shows that the best electrode performance is a trade-off between activation and concentration losses. This is because a decrease in the dimensions of the particles or an increase in its thickness result, on the one hand, in a reduction of the activation polarizations, because of a larger active area for the electrochemical reaction, and, on the other hand, in an increase in the concentration losses due to a more difficult gas diffusion. In particular, in order to understand the impact of concentration losses on the performance of composite electrodes, the simulations have been run with two models, one including and the other one neglecting the mass transport equations. The results show that concentration losses play a role only with thick electrodes composed of small particles, operating at high fuel utilization.

Micro-modeling of porous composite anodes for solid oxide fuel cells

AIChE Journal ◽  
2011 ◽  
Vol 58 (6) ◽  
pp. 1893-1906 ◽  
Author(s):  
Siamak Farhad ◽  
Feridun Hamdullahpur
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Porous Composite ◽  
Micro Modeling ◽  
Composite Anodes

scholarly journals Fabrication and Electrochemical Performance of Zn-Doped La0.2Sr0.25Ca0.45TiO3 Infiltrated with Nickel-CGO, Iron, and Cobalt as an Alternative Anode Material for Solid Oxide Fuel Cells

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 269 ◽  
Author(s):  
Nazan Muzaffar ◽  
Nasima Arshad ◽  
Daniel Drasbæk ◽  
Bhaskar Sudireddy ◽  
Peter Holtappels
Keyword(s):  
Fuel Cells ◽  
Electrochemical Performance ◽  
Solid Oxide Fuel Cells ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Sulphur Poisoning ◽  
Operating Temperatures

In solid oxide fuel cells, doped strontium titinates have been widely studied as anode materials due to their high n-type conductivity. They are used as current conducting backbones as an alternative to nickel-cermets, which suffer degradation due to coking, sulphur poisoning, and low tolerance to redox cycling. In this work, anode backbone materials were synthesized from La0.2Sr0.25Ca0.45TiO3−δ (LSCTA-), modified with 5 wt.% Zn, and infiltrated with nickel (Ni)/ceria gadolinium-doped cerium oxide (CGO), Fe, and Co. The electrodes were further studied for their electrochemical performance using electrochemical impedance spectroscopy (EIS) at open circuit voltage (OCV) in different hydrogen to steam ratios and at various operating temperatures (850–650 °C). Infiltration of electrocatalysts significantly reduced the polarization resistance and among the studied infiltrates, at all operating temperatures, Ni-CGO showed excellent electrode performance. The polarization resistances in 3% and 50% H2O/H2 atmosphere were found to be 0.072 and 0.025 Ω cm2, respectively, at 850 °C, and 0.091 and 0.076 Ω cm2, respectively, at 750 °C, with Ni-CGO. These values are approximately three orders of magnitude smaller than the polarization resistance (25 Ω cm2) of back bone material measured at 750 °C.

Intermediate-Temperature Solid Oxide Fuel Cells with Y0.25Bi0.75O1.5-Ag Cathodes

2005 ◽  
Vol 475-479 ◽  
pp. 1157-1160 ◽  
Author(s):  
Xing Yan Xu ◽  
Chang Rong Xia ◽  
Shou Guo Huang ◽  
Guang Yao Meng
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Spin Coating ◽  
Polarization Resistance ◽  
Interfacial Polarization ◽  
Solid Oxide ◽  
Yttria Stabilized Zirconia ◽  
Intermediate Temperature ◽  
Oxide Fuel ◽  
Stabilized Zirconia

Composites consisting of silver and yttria-stabilized bismuth oxide (YSB) were fabricated and investigated as cathodes for intermediate-temperature solid oxide fuel cells (SOFCs) with thin electrolyte films of yttria-stabilized zirconia (YSZ). The films were deposited using spin coating with YSZ suspension. Comparison of YSB-Ag and conventional La0.8Sr0.2MnO3 (LSM) based cathodes showed that the YSB-Ag composite has better electrochemical performance; Interfacial polarization resistance of YSB-Ag cathode is 0.13 Ωcm2 at 750oC. Power density of the single cell with YSB-Ag cathode was about 535 mW/cm2 at 750oC, while that with LSM-Sm0.2Ce0.8O1.9 cathode was only 329 mW/cm2.

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