scholarly journals Characterization of Solid Oxide Fuel Cells with LSCF-SDC Composite Cathodes

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Gianfranco DiGiuseppe ◽  
Venkatesh Boddapati
Keyword(s):  
Electrochemical Performance ◽  
Structural Damage ◽  
Composite Cathode ◽  
Arrhenius Behavior ◽  
Functional Layer ◽  
Flow Rates ◽  
Composite Cathodes ◽  
Different Temperatures ◽  
Reactant Flow

This paper reports the study of an anode-supported SOFC cell containing an LSCF-SDC composite cathode. The SOFC cell was tested at different temperatures and reactant flow rates. After testing, the cell was sectioned and characterized using SEM/EDS. Such analysis indicated that no structural damage and no significant interdiffusion of elements among the layers occurred. The measured electrochemical performance data at different temperatures indicate an Arrhenius behavior or temperature activated processes. The low-porosity anode functional layer appears to be very sensitive to low hydrogen contents. The electrochemical performance is also affected by changing air flow rates.

Preparation and Characterization of SiC Nanoparticles for ATF-FCM

2018 ◽  
Vol 281 ◽  
pp. 22-27
Author(s):  
Zhao Chen ◽  
Rong Zheng Liu ◽  
Jia Xing Chang ◽  
Ma Lin Liu
Keyword(s):  
Gas Flow ◽  
Chemical Vapor ◽  
Pure Hydrogen ◽  
Fukushima Accident ◽  
Flow Rates ◽  
Sic Nanoparticles ◽  
Hydrogen Flow ◽  
Different Temperatures ◽  
Carrier Gas Flow

Accident Tolerant fuel (ATF) concept was put forward after the Fukushima accident. Among different kinds of ATF, Fully Ceramic Microencapsulated Fuels (FCM) have been paid more and more attention in recent years. SiC matrix is one of the important constituent parts in FCM fuel system, which is sintered from kinds of SiC powders. In this study, SiC nanoparticles were prepared by Fluidized Bed Chemical Vapor Deposition (FB-CVD) method using Hexamethyldisilane (HMDS) as precursor, aimed at reducing the sintering temperature and pressure of FCM-SiC matrix. Experiments of different temperatures with different argon gas ratios were carried out. It was found that good crystal SiC could be obtained from 850°C to 1250°C, under pure hydrogen or H2: Ar=15:1. Different H2 carrier gas flow rate tests were also conducted. With the increase of hydrogen flow rates, the SiC was transformed from 3C-SiC to other types, such as 6H or 15R, but no significant effect was found on particle shape. Based on the characterizations of XRD, SEM and TEM, the results showed the spherical SiC nanoparticles could be obtained as well as 20 nanometers in diameter at the condition of 1150°C, H2: Ar=15:1, under different hydrogen flow rates. Different hydrogen flow rates had little influence on the particle size of SiC nanoparticles.

Evaluation and Optimization of Ba0.2Sr0.8Co0.9Nb0.1O3-δ-Gd0.1Ce0.9O1.95 Composite Cathodes for IT-SOFCs

2014 ◽  
Vol 787 ◽  
pp. 221-226
Author(s):  
Lei Lei Zhang ◽  
Jin Hua Huang ◽  
Zhao Yuan Song ◽  
Yi Dan Fu ◽  
Mo Liu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Electrochemical Performance ◽  
Vacancy Concentration ◽  
Composite Cathode ◽  
Oxygen Vacancy Concentration ◽  
Promising Candidate ◽  
Thermal Expansion Coefficients ◽  
Composite Cathodes ◽  
Expansion Coefficients ◽  
Power Densities

Ba0.2Sr0.8Co0.9Nb0.1O3-δ(BSCN0.2)-xGd0.1Ce0.9O1.95(GDC) (x = 10, 20, 30 and 40 wt.%) composite cathodes were investigated for the potential application in the IT-SOFCs. The results of chemical compatibility measurement show that a small number of Gd and/or Ce ions may melt into the lattice of BSCN0.2 to form BSCN0.2-GDC solid solution. Thermal expansion coefficients effectively reduced by the incorporation of GDC. The electrochemical performance of BSCN0.2-xGDC composite cathodes increased with increasing x from 10 to 30 wt.%. When x = 30 wt.%, the area specific resistances were only 0.040 and 0.017 Ω cm2at 750 and 800oC, respectively. This improved electrochemical performance is attributed to the good thermal expansion match between BSCN0.2-xGDC composite cathode and GDC electrolyte, and the increased oxygen vacancy concentration. With further increasing x, the electrochemical performance of the composite cathode decreased. This result may be due to the ambipolar resistance model of porous composite cathode and the poor electrical conductivity of BSCN-40GDC. The maximum power densities of a BSCN0.2-30GDC/La0.9Sr0.1Ga0.8Mg0.2O3-δ/NiO-Sm0.2Ce0.8O1.9single-cell achieve 537 and 722 mW cm-2at 750oC and 800oC, respectively. These results indicate that the BSCN0.2-30GDC composite cathode is a promising candidate for IT-SOFC.

Influence of Sintering Temperature on the Electrochemical Performance of Sm0.5-XGdxSr0.5Co 3-δ/Gd0.1Ce0.9O1.95 Composite Cathode

2011 ◽  
Vol 239-242 ◽  
pp. 1613-1616
Author(s):  
Ji Min Zhai ◽  
Xi Wen Song ◽  
Fen Zhou ◽  
Sheng Li An
Keyword(s):  
Solid State ◽  
Impedance Spectroscopy ◽  
Sintering Temperature ◽  
Perovskite Phase ◽  
Solid State Reaction Method ◽  
Composite Cathode ◽  
Reaction Method ◽  
Composite Cathodes ◽  
Different Temperatures ◽  
Alternative Current

In this paper, Sm0.5-xGdxSr0.5CoO3-δ(SGSC, x=0 and 0.2) powders were prepared using the solid-state reaction method. Their structure was identified by XRD. All powders formed the perovskite phase when calcined at 1100°C for 5 h. Sm0.3Gd0.2Sr0.5CoO3-δ/Gd0.1Ce0.9O1.95slurrieswere screen printed onto both surfaces of Gd0.1Ce0.9O1.95electrolyte and fired at different temperatures to fabricate the composite cathodes. The electrochemical property of the composite cathodes was characterized by the alternative current impedance spectroscopy. The impedance resistance of the composite cathodes increased with the increase of sintering temperature. For instance, the impedance resistance of the composite cathode fired at 1000 °C was 0.0875 Ω·cm2at 700 °C, while it was 0.175 Ω·cm2when fired at 1100 °C.

scholarly journals Effects of the LiFePO4 content and the preparation method on the properties of (LiFePO4+AC)/Li4Ti5O12 hybrid batterycapacitors

2010 ◽  
Vol 75 (9) ◽  
pp. 1259-1269 ◽  
Author(s):  
Xue Hu ◽  
Zi Lin ◽  
Li Liu ◽  
Jian Huai ◽  
Hua Deng
Keyword(s):  
Electrochemical Performance ◽  
Cathode Materials ◽  
Preparation Method ◽  
Composite Cathode ◽  
Cycle Performance ◽  
Cyclic Voltammograms ◽  
Capacity Loss ◽  
In Situ Method ◽  
Composite Cathodes

Two composite cathode materials containing LiFePO4 and activated carbon (AC) were synthesized by an in-situ method and a direct mixing technique, which are abbreviated as LAC and DMLAC, respectively. Hybrid battery-capacitors LAC/Li4Ti5O12 and DMLAC/Li4Ti5O12 were then assembled. The effects of the content of LiFePO4 and the preparation method on the cyclic voltammograms, the rate of charge-discharge and the cycle performance of the hybrid batterycapacitors were investigated. The results showed the overall electrochemical performance of the hybrid battery-capacitors was the best when the content of LiFePO4 in the composite cathode materials was in the range from 11.8 to 28.5 wt. %, while the preparation method had almost no impact on the electrochemical performance of the composite cathodes and hybrid battery-capacitors. Moreover, the hybrid batterycapacitor devices had a good cycle life performance at high rates. After 1000 cycles, the capacity loss of the DMLAC/Li4Ti5O12 hybrid batterycapacitor device at 4 C was no more than 4.8 %. Moreover, the capacity loss would be no more than 9.6 % after 2000 cycles at 8?C.

Preparation and characterization of lead ruthenate based composite cathodes for SOFC applications

2004 ◽  
Vol 835 ◽  
Author(s):  
Vincenzo Esposito ◽  
Enrico Traversa ◽  
Eric D. Wachsman
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Xrd Analysis ◽  
Composite Electrodes ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Composite Cathodes ◽  
Different Temperatures ◽  
Eis Measurements

ABSTRACTNanometric pyrochlore lead ruthenate (Pb2Ru2O6.5) powders were prepared using a new chemical route as a possible candidate for cathode materials in solid oxide fuel cells (SOFCs). Pb2Ru2O6.5 was mixed with yttria-stabilized zirconia (YSZ) and erbia-stabilized bismuth oxide (ESB) to fabricate porous composite electrodes. Pure pyrochlore or composite electrodes were deposited as thick films onto YSZ and ESB electrolytes. Powders and films were analyzed using X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM). Electrochemical features of the electrodes were investigated using electrochemical impedance spectroscopy (EIS) measurements at different temperatures in air for symmetric cells. The composite electrodes were compared to single Pb2Ru2O6.5 phase electrodes to evaluate the effect on polarization of the addition of the pure ionic conductor phase in the electrodes.

Performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag Composite Cathode Materials for IT-SOFCs

2011 ◽  
Vol 311-313 ◽  
pp. 2309-2314 ◽  
Author(s):  
Wen Xia Zhu ◽  
Zhe Lü ◽  
Le Xin Wang ◽  
Xiao Yan Guan ◽  
Xin Yan Zhang
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Electrode Polarization ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Composite Cathodes ◽  
Reduced Temperature ◽  
Resistance Value

°Abstract. In order to develop new cathodes for reduced temperature SOFCs, Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag composite cathode was investigated in intermediate-temperature Solid Oxide Fuel Cells (IT-SOFCs). The XRD results suggested that no chemical reactions between BSCF and Ag in the composite cathode were found. The resistance measurements showed that the addition of Ag into BSCF improved electrical conductivity of pure BSCF, and the improved conductivity resulted in attractive cathode performance. In addition, electrochemical impedance spectra exhibited the better performance of BSCF-Ag composite cathodes than pure BSCF, e.g., the polarization resistance value of BSCF-Ag was only 0.36Ω cm2 at 650°C, which was nearly 80% lower than that of BSCF electrode. Polarization curves showed the overpotential decreased with the addition of Ag. The current density value of BSCF-Ag was 0.88Acm-2 under –120mV, about five times of that BSCF measured at 650°C. As a summary, compared to a pure BSCF cathode, it was found that adding Ag in the cathode enhanced the BSCF performance significantly.

Synthesis and Characterization of Nanocrystalline ZnO Powders by a Direct Thermal Decomposition Route Using Zinc Nitrate Hexahydrate

2013 ◽  
Vol 770 ◽  
pp. 68-71 ◽  
Author(s):  
Supphadate Sujinnapram ◽  
Uraiphorn Termsuk ◽  
Atcharawan Charoentam ◽  
Sutthipoj Sutthana
Keyword(s):  
Thermal Decomposition ◽  
Crystallization Temperature ◽  
Zinc Nitrate ◽  
Zinc Nitrate Hexahydrate ◽  
Absorption Peak ◽  
Synthesis And Characterization ◽  
Nitrate Hexahydrate ◽  
Different Temperatures ◽  
Zno Powders

The nanocrystalline ZnO powders were synthesized by a direct thermal decomposition using zinc nitrate hexahydrate as starting materials. The precursor was characterized by TG-DTA to determine the thermal decomposition and crystallization temperature which was found to be at 325 oC. The precursors were calcined at different temperatures of 400, 500, and 600°C for 4 h. The structure of the prepared samples was studied by XRD, confirming the formation of wurtzite structure. The synthesized powders exhibited the UV absorption below 400 nm (3.10 eV) with a well defined absorption peak at around 285 nm (4.35 eV). The estimated direct bandgaps were obtained to be 3.19, 3.16, and 3.14 eV for the ZnO samples thermally decomposed at 400, 500, and 600°C, respectively.

scholarly journals One-Step Preparation of Biochar Electrodes and Their Applications in Sediment Microbial Electrochemical Systems

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 508
Author(s):  
Kui You ◽  
Zihan Zhou ◽  
Chao Gao ◽  
Qiao Yang
Keyword(s):  
Output Power ◽  
Electrode Materials ◽  
Maximum Output Power ◽  
Composite Cathode ◽  
Maximum Output ◽  
Electrochemical Systems ◽  
Composite Cathodes ◽  
One Step ◽  
Microbial Electrochemical Systems ◽  
Hot Melt

Biochar is a kind of carbon-rich material formed by pyrolysis of biomass at high temperature in the absence or limitation of oxygen. It has abundant pore structure and a large surface area, which could be considered the beneficial characteristics for electrodes of microbial electrochemical systems. In this study, reed was used as the raw material of biochar and six biochar-based electrode materials were obtained by three methods, including one-step biochar cathodes (BC 800 and BC 700), biochar/polyethylene composite cathodes (BP 5:5 and BP 6:4), and biochar/polyaniline/hot-melt adhesive composite cathode (BPP 5:1:4 and BPP 4:1:5). The basic physical properties and electrochemical properties of the self-made biochar electrode materials were characterized. Selected biochar-based electrode materials were used as the cathode of sediment microbial electrochemical reactors. The reactor with pure biochar electrode (BC 800) achieves a maximum output power density of 9.15 ± 0.02 mW/m2, which increases the output power by nearly 80% compared with carbon felt. When using a biochar/polyaniline/hot-melt adhesive (BPP 5:1:4) composite cathode, the output power was increased by 2.33 times. Under the premise of ensuring the molding of the material, the higher the content of biochar, the better the electrochemical performance of the electrodes. The treatment of reed powder before pyrolysis is an important factor for the molding of biochar. The one-step molding biochar cathode had satisfactory performance in sediment microbial electrochemical systems. By exploring the biochar-based electrode, waste biomass could be reused, which is beneficial for the environment.

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