scholarly journals Degradation of Ni-YSZ and Ni-GDC fuel cells after 1000 h operation: Analysis of different overpotential contributions according to electrochemical and microstructural characterization

2022 ◽  
Vol 334 ◽  
pp. 04011
Author(s):  
Aiswarya Krishnakumar Padinjarethil ◽  
Fiammetta Rita Bianchi ◽  
Barbara Bosio ◽  
Anke Hagen

Solid Oxide Fuel Cell (SOFC) technologies are emerging as potential power generation units with limited environmental impacts. However, the main challenges towards large scale commercial applications are high costs and low lifetime compared to currently used technologies. The present study aims at understanding degradation mechanisms in SOFCs through both experimental and modelling approaches. For this purpose, two state of the art fuel cell configurations based on Ni cermet fuel electrode (either YSZ-Yttrium Stabilised Zirconia or GDC-Gadolinium Doped Ceria), YSZ electrolyte and LSCF (Lanthanum Strontium Cobalt Ferrite oxide) air electrode were chosen. The cells were tested for 1000 hours with H2 rich mixture as fuel feed and air as oxidant. Cells were characterised at several H2/H2O ratios and temperatures with air or oxygen fed to the air electrode using different techniques. These allowed the identification of kinetic parameters to be implemented in an in-house 2D Fortran based model. The model was able to successfully simulate global cell behaviour as a function of local features, and it was validated with experimental I-V curves recorded prior and post durability operation. Moreover, post-mortem microstructure characterisation was also performed to fine-tune the model towards a more accurate prediction of the degradation influence on cell performance.

Author(s):  
W.T. Ju ◽  
S.H. Hong

Abstract The atmospheric pressure plasma spray processes for functional layers of the tubular solid oxide fuel cell are developed to build a fuel cell structure consisting of air electrode, ceramic electrolyte, and fuel electrode. Further more the characteristics of each film are also investigated. The layers of LSM (La0.65Sr0.35MnO3) air electrode and Ni/8YSZ fuel electrode have porosities of 23 ~32 % sufficient for supplying fuel and oxidant gases efficiently to electrochemical reaction interfaces. The measured electrical conductivities of the electrodes are higher than 90 S/cm at 1000 °C, which satisfy the requirement as the current collecting electrodes. The YSZ electrolyte film has a high ionic conductivity of 0.07 S/cm at 1000 °C, but shows a bit too porous to block the oxygen molecule penetration through it. A unit tubular SOFC is fabricated by the optimized plasma spray processes for depositing each functional film and forming a porous cylindrical supporting tube of the cell, and turns out to have a promising capability of electricity generation.


Author(s):  
Borja Oyarza´bal ◽  
Michael R. von Spokovsky ◽  
Michael W. Ellis ◽  
J. Ricardo Mun˜oz ◽  
Nikolaos G. Georgopoulos

The application of a decomposition methodology to the synthesis/design optimization of a stationary cogeneration fuel cell sub-system for residential/commercial applications is the focus of this paper. To accomplish this, a number of different configurations for the fuel cell sub-system were considered. The most promising candidate configuration, which combines features of different configurations found in the literature, is chosen for detailed thermodynamic, geometric, and economic modeling both at design and off-design. The case is then made for the usefulness and need of decomposition in large-scale optimization. The types of decomposition strategies considered are conceptual/time and physical decomposition. Specific solution approaches to the latter, namely Local-Global Optimization (LGO) are outlined in the paper. Conceptual/time decomposition and physical decomposition using the LGO approach are applied to the fuel cell sub-system. These techniques prove to be useful tools for simplifying the overall synthesis/design optimization problem of the fuel cell sub-system. Finally, the results of the decomposed synthesis/design optimization of the fuel cell sub-system indicate that this sub-system is more economical for a relatively large cluster of residences (i.e. 50). To achieve a unit cost of power production of less than 10 cents/kWh on an exergy basis requires the manufacture of more than 1500 fuel cell sub-system units per year. In addition, based on the off-design optimization results, the fuel cell sub-system is unable by itself to satisfy the winter heat demands. Thus, the case is made for integrating the fuel cell sub-system with another sub-system, namely, a heat pump, to form what is called a total energy system.


Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 469-474 ◽  
Author(s):  
A. Gamliel ◽  
A. Grinstein ◽  
Y. Peretz ◽  
L. Klein ◽  
A. Nachmias ◽  
...  

The use of gas-impermeable films to reduce the dosage of methyl bromide (MB) required to control Verticillium wilt in potatoes was examined in field experiments, conducted in soils naturally infested with Verticillium dahliae. The incidence and severity of Verticillium wilt were significantly reduced (by 74 to 94%) by fumigation with MB at 50 g/m2 under standard low density polyethylene (LDPE) or at 25 g/m2 under gas-impermeable films. Fumigation at 25 g/m2 under LDPE was less effective. Disease severity was inversely correlated (r2 = 0.89 to 0.91) with chlorophyll content in the leaves. Fumigation also reduced (by 89 to 100%) stem colonization by the pathogen. Potato yield in the fumigated plots was significantly higher (26 to 69%), than in their nonfumigated counterparts, and was inversely correlated with disease index (r2 = 0.69 to 0.9). The percentage of high-value tubers (above 45 g) was 52 to 56% of total yield in the fumigated plots as compared with 32 to 40% in the nonfumigated controls. Thus, fumigation also improved the commercial quality of tuber yield. Effective control of V. dahliae and yield increases following MB fumigation at the recommended dosage or at a reduced dosage with gas-impermeable films was also observed in a consecutive crop. These results were verified in a large-scale field experiment using commercial applications, further demonstrating the feasibility of reducing MB dosages under farm conditions, without reducing its effectiveness in terms of disease control and yield improvement.


Author(s):  
M. Minutillo ◽  
E. Jannelli ◽  
F. Tunzio

The main objective of this study is to evaluate the performance of a proton exchange membrane (PEM) fuel cell generator operating for residential applications. The fuel cell performance has been evaluated using the test bed of the University of Cassino. The experimental activity has been focused to evaluate the performance in different operating conditions: stack temperature, feeding mode, and fuel composition. In order to use PEM fuel cell technology on a large scale, for an electric power distributed generation, it could be necessary to feed fuel cells with conventional fuel, such as natural gas, to generate hydrogen in situ because currently the infrastructure for the distribution of hydrogen is almost nonexistent. Therefore, the fuel cell performance has been evaluated both using pure hydrogen and reformate gas produced by a natural gas reforming system.


Author(s):  
J. S. V. Siva Kumar ◽  
P. Mallikarjunarao

<p>The automobile industry is one of the major industries that are having its new innovations at a great pace according to the requirements of the day-to-day life. Due to the usage of conventional vehicles on a large scale which usually use petroleum products as fuel, is leading to a vast environmental effect, mainly due to the emission of greenhouse gases. So in order to reduce the ill effects of the greenhouse gas emissions great efforts are being put in   manufacturing of electrical vehicles. Among the currently available greenhouse technologies the fuel cell provides high energy density in spite of its expenses. So, in this aspect a required mechanism has to be adopted to make it energy efficient and affordable. In order to overcome the drawback of fuel cell i.e. low output voltage, the boost converters are to be used and to be more precise Non-isolated Interleaved Double Dual Boost (IDDB) converters are recommended which makes it efficient and also the reduction of overall vehicle weight can be achieved. The LQR control technique is applied in this work to make the transient response of the fuel cell powered IDDB converter for various load conditions effective. The verification of results is done with simulation techniques using MATLAB/Simulink.</p>


2010 ◽  
Vol 124 (2-3) ◽  
pp. 1015-1021 ◽  
Author(s):  
Roberta G. Toro ◽  
Davide M.R. Fiorito ◽  
Maria E. Fragalà ◽  
Antonio Barbucci ◽  
Maria P. Carpanese ◽  
...  

2021 ◽  
Vol 103 (1) ◽  
pp. 581-590
Author(s):  
Claire Julie Ferchaud ◽  
Frans Berkel ◽  
Loek Berkeveld ◽  
Miranda Heijink-Smith ◽  
Jakobert Veldhuis ◽  
...  

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