摘要 :
An electrode supported Ni-YSZ/YSZ/Ni-YSZ symmetric cell was studied in life tests with constant current and switching current operation. At a current density of 0.2 A/cm~2, there was no evidence of degradation. The cell electroche...
展开
An electrode supported Ni-YSZ/YSZ/Ni-YSZ symmetric cell was studied in life tests with constant current and switching current operation. At a current density of 0.2 A/cm~2, there was no evidence of degradation. The cell electrochemical performance degraded slightly during life tests at current densities ≥ 0.8 A/cm~2, with the ohmic resistance increasing and polarization resistance decreasing. The electrode/electrolyte interface structure was found to be seriously degraded after the life tests, with the formation of interfacial voids. In addition, grain boundary voids were observed within the YSZ electrolyte, especially after constant current operation. These observations presumably explain the observed electrolyte resistance increase. Both Ni and YSZ nanoparticles were observed in the electrode functional layers after life tests, possibly explaining the decrease of polarization resistance.
收起
摘要 :
In conventional solid oxide electrolysis mode, most of the electric power is consumed to overcome the high chemical potential in forcing the oxygen to diffuse through the electrolyte. In this paper, a novel methane-assisted H_2O/C...
展开
In conventional solid oxide electrolysis mode, most of the electric power is consumed to overcome the high chemical potential in forcing the oxygen to diffuse through the electrolyte. In this paper, a novel methane-assisted H_2O/CO_2 co-electrolyzer was designed by combining solid oxide electrolysis cell (SOEC) with partial oxidation of methane (POM) to generate syngas in both sides. In POM-SOEC mode, methane is fed to the oxygen electrode to react with the oxygen produced by the electrolysis process, thus to reduce the chemical potential. Experiment performed on the Ni-YSZ/YSZ/SFM-YSZ single cell showed a voltage reduction from 1.3 V to 0.3 V compared to the conventional electrolysis mode at the same current density.
收起
摘要 :
Samples of Na-β"-alumina + yttria-stabilized (YSZ) were made by vapor phase conversion of sintered a-alumina + YSZ. The samples were then treated in molten LiNO_3 to convert Na-β"-alumina into Li-β"-alumina by ion exchange. The...
展开
Samples of Na-β"-alumina + yttria-stabilized (YSZ) were made by vapor phase conversion of sintered a-alumina + YSZ. The samples were then treated in molten LiNO_3 to convert Na-β"-alumina into Li-β"-alumina by ion exchange. The resulting two phase material is a Li~+-ion conductor with room temperature ionic conductivity of ~2 x 10~(-4) to 7.5 x 10~(-4) Scm~(-1). The corresponding activation energy is 0.18 eV. Two lithium batteries of LMO+C||Li~+/Na~+- β"-alumina + YSZ ||Li structure were constructed using the same ion exchanged disc of 1 mm thickness over a period two months apart. Both batteries displayed a stable OCV of around 3.2 V at room temperature. No chemical and mechanical degradation of the solid electrolyte disc was observed over the testing period, indicating a high stability of the reported solid electrolyte against lithium metal. Thermodynamic activity of lithium is estimated to be {formula} in LMO, and {formula} in Li_2O.
收起
摘要 :
We compared the densification behavior of three different types of 8 mol% yttria-stabilized zirconia (YSZ) powders used as the electrolyte for solid oxide fuel cells (SOFCs): (i) T2-8Y from Tosoh (Japan), (ii) MELox 8Y from MEL Ch...
展开
We compared the densification behavior of three different types of 8 mol% yttria-stabilized zirconia (YSZ) powders used as the electrolyte for solid oxide fuel cells (SOFCs): (i) T2-8Y from Tosoh (Japan), (ii) MELox 8Y from MEL Chemicals (UK), and (iii) YSZ-HT from Huatsing Power (China). The YSZ powders were pressed to form disc-shaped pellets that were sintered at different temperatures ranging 1200-1400°C. Among the three YSZ powders, MELox 8Y showed the best densification behavior at lower sintering temperatures with 93 and 96% of the theoretical density at 1250 and 1300°C, respectively. Although YSZ-HT showed higher sintering rate than TZ-8Y, a sintering temperature of 1350°C was required for both the powders to reach a theoretical density>95%. Our results indicate that different factors besides the particle size play a significant role in determining the sintering rate and densification behavior of the YSZ electrolyte.
收起
摘要 :
Ni-Ni_3Sn-YSZ and Ni-YSZ anodes were incorporated into metal-supported SOFCs that consisted of a porous metal support (Sandvik Sanergy),samaria-doped ceria(SDC)barrier layer, anode as previously described, YSZ electrolyte, and La_...
展开
Ni-Ni_3Sn-YSZ and Ni-YSZ anodes were incorporated into metal-supported SOFCs that consisted of a porous metal support (Sandvik Sanergy),samaria-doped ceria(SDC)barrier layer, anode as previously described, YSZ electrolyte, and La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)-SDC cathode. Cells were tested at 750°C with air as the oxidant and fuel consisting of 65% CH4, 32% H_2,and 3% H_2O. The cells were held at a current density of 0.15 A.cm~(-2) for 500 hours. The cell without tin in the anode began to degrade after approximately 200 hours and catastrophically failed at approximately 425 hours. After testing,we observed that the anode had disintegrated, and as a result, the electrolyte and cathode were completely detached from the metal support. On the other hand, the cell with an anode containing tin did not catastrophically fail, and the cell remained intact after 500 hours of operation. Over 500 hours, the cell potential degraded from 0.841 V to 0.743 V,and scanning electron micrographs showed that the anode had delaminated from the electrolyte in some areas. Nonetheless, the cell with the Ni-Ni_3Sn-YSZ anode degraded significantly less than the cell containing a Ni-YSZ anode, suggesting that the addition of Ni_3Sn to an anode could be a useful strategy for improving durability of SOFC anodes using hydrocarbon fuels.
收起
摘要 :
Alumina-zirconia composites Al_2O_3-20 vol. % yttria stabilized zirconia containing two types of yttria stabilized zirconia: 3mol% yttria doped ZrO_2 and 8mol% yttria doped ZrO_2 were consolidated very rapidly to full density by h...
展开
Alumina-zirconia composites Al_2O_3-20 vol. % yttria stabilized zirconia containing two types of yttria stabilized zirconia: 3mol% yttria doped ZrO_2 and 8mol% yttria doped ZrO_2 were consolidated very rapidly to full density by high frequency induction heating sintering (HFIHS). A comparison between 3YSZ and 8YSZ as a second phase toughening alumina has been made. Effects of sintering temperature on the mechanical properties have been studied. The consolidated samples were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The microhardness, strength and toughness of the composites are determined. The results showed that, 3YSZ is most effective as a second phase toughening alumina then 8YSZ. Al_2O_3-3YSZ composites with higher mechanical properties and small grain size were successfully developed at relatively low temperatures through this technique.
收起
摘要 :
Alumina-zirconia composites Al_2O_3-20 vol. % yttria stabilized zirconia containing two types of yttria stabilized zirconia: 3mol% yttria doped ZrO_2 and 8mol% yttria doped ZrO_2 were consolidated very rapidly to full density by h...
展开
Alumina-zirconia composites Al_2O_3-20 vol. % yttria stabilized zirconia containing two types of yttria stabilized zirconia: 3mol% yttria doped ZrO_2 and 8mol% yttria doped ZrO_2 were consolidated very rapidly to full density by high frequency induction heating sintering (HFIHS). A comparison between 3YSZ and 8YSZ as a second phase toughening alumina has been made. Effects of sintering temperature on the mechanical properties have been studied. The consolidated samples were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The microhardness, strength and toughness of the composites are determined. The results showed that, 3YSZ is most effective as a second phase toughening alumina then 8YSZ. Al_2O_3-3YSZ composites with higher mechanical properties and small grain size were successfully developed at relatively low temperatures through this technique.
收起
摘要 :
Alumina-zirconia composites Al_2O_3-20 vol. percent yttria stabilized zirconia containing two types of yttria stabilized zirconia: 3mol percent yttria doped ZrO_2 and 8mol percent yttria doped ZrO_2 were consolidated very rapidly ...
展开
Alumina-zirconia composites Al_2O_3-20 vol. percent yttria stabilized zirconia containing two types of yttria stabilized zirconia: 3mol percent yttria doped ZrO_2 and 8mol percent yttria doped ZrO_2 were consolidated very rapidly to full density by high frequency induction heating sintering (HFIHS). A comparison between 3YSZ and 8YSZ as a second phase toughening alumina has been made. Effects of sintering temperature on the mechanical properties have been studied. The consolidated samples were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The microhardness, strength and toughness of the composites are determined. The results showed that, 3YSZ is most effective as a second phase toughening alumina then 8YSZ. Al_2O_3-3YSZ composites with higher mechanical properties and small grain size were successfully developed at relatively low temperatures through this technique.
收起
摘要 :
YSZ/Ni composites were fabricated by gelcasting a mixture of alumina and nickel oxide, followed by reduction-sintering process. The rheological behavior and the optimum dispersant quantity of YSZ/NiO suspension were examined to de...
展开
YSZ/Ni composites were fabricated by gelcasting a mixture of alumina and nickel oxide, followed by reduction-sintering process. The rheological behavior and the optimum dispersant quantity of YSZ/NiO suspension were examined to determined best dispersion state of YSZ/NiO suspension for casting. Material characterizations were carried through XRD, TGA and SEM. The results showed hydrogen reduction of NiO in the green body was accomplished successfully via pore channels of debined organic chemical volume. The gelcasting process for the ceramic/metal composite anode materials present great advantages for solid oxide fuel cell.
收起
摘要 :
YSZ/Ni cmoposites were fabricated by gelcasting a mixture of alumina and nickel oxide, followed by reduction-sintering process. The rheological behavior and the optimum dispersant quantity of YSZ/NiO suspension were examined to de...
展开
YSZ/Ni cmoposites were fabricated by gelcasting a mixture of alumina and nickel oxide, followed by reduction-sintering process. The rheological behavior and the optimum dispersant quantity of YSZ/NiO suspension were examined to determined best dispersion state of YSZ/NiO suspension for casting. Material characterizations were carried through XRD, TGA and SEM The results showed hydrogen reduction of NiO in the green body was accomplished successfully via pore channels of debined organic chemical volume. The gelcasting process for the ceramic/metal composite anode materials present great advantages for solid oxide fuel cell.
收起
原文获取