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1.
Ni-Al2O3 cermet supported tubular solid oxide fuel cells(SOFCs)with different cathodes were fabricated by thermal spraying.The anode,electrolyte and cathode were deposited by atmospheric plasma spraying(APS)aimed at reducing the manufacturing cost of SOFCs.Three porous composite cathodes of lanthanum strontium manganite(LSM)and yttria-stabilized zirconia(YSZ),lanthanum strontium cobalt oxide(LSC)and YSZ,LSC and scandia-stabilized zirconia(ScSZ)were prepared to investigate influence of cathode constitutions on the cell’s performance.The electrode polarization can be improved through using a composite cathode.The maximum power density of the cell with APS YSZ electrolyte and LSC/ScSZ composite cathode is increased about 12%than pure LSM cathode.The maximum output power density of the cell with APS ScSZ electrolyte and LSC/ScSZ composite cathode reaches 1.0 W/cm 2 at 1000 o C.The further optimization of the performance of plasma-sprayed composite cathode can be made through improving the interface contact between YSZ electrolyte and composite cathode. 相似文献
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The performance of multi-layer (1-x)La0.8Sr0.2MnO3/xYSZ graded composite cathodes was studied as electrode materials for intermediate solid oxide fuel cells (SOFC). The thermal expansion coefficient, electrical conductivity, and electrochemical performance of multi-layer composite cathodes were investigated. The thermal expansion coefficient and electrical conductivity decreased with the increase in YSZ content. The (1-x)La0.8Sr0.2MnO3/xYSZ composite cathode greatly increased the length of the active triple phase boundary line (TPBL) among electrode, electrolyte, and gas phase, leading to a decrease in polarization resistance and an increase in polarization current density. The polarization current density of the triple-layer graded composite cathode (0.77 A/cm2) was the highest and that of the monolayer cathode (0.13 A/cm2) was the lowest. The polarization resistance (Rp) of the triple-layer graded composite cathode was only 0.182Ω·cm2 and that of the monolayer composite cathode was 0.323Ω·cm2. The power density of the triple-layer graded composite cathode was the highest and that of the monolayer composite cathode was the lowest. The triple-layer graded composite cathode had superior performance. 相似文献
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The performance of multi-layer (1 − x) La0.8Sr0.2MnO3/x YSZ graded composite cathodes was studied as electrode materials for intermediate solid oxide fuel cells (SOFC). The thermal expansion coefficient, electrical conductivity, and electrochemical performance of multi-layer composite cathodes were investigated. The thermal expansion coefficient and electrical conductivity decreased with the increase in YSZ content. The (1 -x)La0.8Sr0.2MnO3/x YSZ composite cathode greatly increased the length of the active triple phase boundary line (TPBL) among electrode, electrolyte, and gas phase, leading to a decrease in polarization resistance and an increase in polarization current density. The polarization current density of the triple-layer graded composite cathode (0.77 A/cm2) was the highest and that of the monolayer cathode (0.13 A/cm2) was the lowest. The polarization resistance (Rp) of the triple-layer graded composite cathode was only 0.182 ω·cm2 and that of the monolayer composite cathode was 0.323 ω·cm2. The power density of the triple-layer graded composite cathode was the highest and that of the monolayer composite cathode was the lowest. The triple-layer graded composite cathode had superior performance. 相似文献
4.
Influence of phase boundary reactions during metal oxidation. Investigation into the sulfidation of silver in sulphur vapour The present paper is concerned with theoretical and experimental investigations into the simultaneous influence of two phase boundary reactions on the kinetics of the sulfidation of silver in sulphur vapour. The two phase boundary reactions involved are
- a diffusion of silver through the phase boundary between solid silver and solid silver sulfide, and
- b absorption by silver sulfide of sulphur from the gas phase.
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等离子喷涂技术可以对陶瓷涂层的微观结构进行调控设计,因此在制备固体氧化物燃料电池方面具有独特的优势。基于等离子喷涂方法,可以直接制备或经过后处理获得致密的电解质涂层。采用等离子喷涂技术也可以制备高性能的多孔阳极和阴极,并可对钙钛矿结构阴极材料的成分和晶体结构进行调控。文中介绍了目前国内外采用涂层制备电池的方法,主要探讨了热喷涂方法制备电解质涂层的特点,对存在的问题和可行思路进行了讨论,并探讨了基于提高三相反应界面长度来制备高性能电极的方法。由于固体氧化物燃料全电池各功能层都有可能通过热喷涂方法制备,因此该方法在固体氧化物燃料电池结构设计具有巨大的潜力。 相似文献
7.
Xiao-Ming Wang Chang-Jiu Li Cheng-Xin Li Guan-Jun Yang 《Journal of Thermal Spray Technology》2010,19(1-2):311-316
Plasma-sprayed yttria-stabilized zirconia (YSZ) can be potentially employed as electrolyte layers in solid oxide fuel cells (SOFCs). The formation of a structured electrolyte surface characterized by convex micro deposits generated by only partially molten particles at spraying will increase the specific surface area and subsequently improve the output performance of SOFCs. However, using completely molten YSZ particles during plasma spraying leads to the formation of locally flat surface. In this study, flame spraying was employed to deposit YSZ particles on YSZ substrate using surface-melted particles. The deposition was carried out at different spray distances on YSZ substrate preheated to 650 °C. The surface and cross-section morphology of YSZ particles were characterized by SEM. The electrochemical behavior of single cell with the structured cathode was characterized by the electrochemical impedance spectroscopy. The results show that spray distance exhibits significant influence on the morphology of deposited YSZ particles. The cathode polarization of a structured cathode was decreased by about 30-43% compared to a flat cathode at different temperatures. 相似文献
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《Surface & coatings technology》1986,27(4):311-315
Small angle X-ray scattering (SAXS) studies have been performed on Cu-Cd alloys obtained using electrodeposition from an ethylenediamine electrolyte in the cathode potential range from -500 mV to -800 mV. SAXS results confirm the existence of at least two phases in these alloys (a solid solution of cadmium in copper and a phase enriched in cadmium) and also indicate that the phase enriched in cadmium has a complex structure which is independent of cathode potential. 相似文献
10.
Cheng-Xin Li Zhun-Zhun Wang Shuai Liu Chang-Jiu Li 《Journal of Thermal Spray Technology》2013,22(5):640-645
A cermet-supported tubular SOFC was fabricated using thermal spray. The cell performance was investigated at temperatures from 750 to 900 °C and pressures from 0.1 to 0.5 MPa to examine the effect of operating gas pressure on the cell performance. The influence of gas pressure on the cathodic polarization was studied through the electrochemical impedance approach to examine the controlling electrochemical processes during cell operation. Results show that increasing the operating gas pressure improves the power output performance significantly. When the gas pressure is increased from 0.1 to 0.3 MPa, the maximum power density is increased by a factor of 32% at a temperature of 800 °C. The cathode polarization decreases significantly with the increase of the gas pressure. The electrochemical analysis shows that the main control processes of the cathode reaction are the oxygen species transfer at the three-phase boundary and oxygen diffusion on the surface or in the bulk of the cathode, which are enhanced with increasing gas pressure. 相似文献
11.
It has been shown by means of a potentiostatic technique that both the anodic and the cathodic behaviour of steel are inhibited in an aqueous red lead slurry with 0.1 M sodium perchlorate as supporting electrolyte. The oxygen reduction on the cathode takes place at a slower rate in the slurry than in the pure electrolyte solution. According to scanning electron microscopy with microprobe analysis and Guinier X-ray diffraction phase analysis, the layer formed on the cathode at about ?1100 mV consisted of metallic lead deposited from solute lead species. At more negative potentials and unidentified phase appeared. 相似文献
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A. Filzwieser K. Hein G. Mori 《JOM Journal of the Minerals, Metals and Materials Society》2002,54(4):28-31
The knowledge of limiting current density and thickness of diffusion boundary layer is particularly important in improving
space-time-yield of electrolysis and especially of high current-density electrolysis. Both natural and forced convection of
electrolyte flow are considered in the presented computational fluid dynamics model for calculation of these values. Natural
convection is modeled by implementation of a source term at the cathode surface for copper concentration according to Faraday’s
law, which allows calculation of electrolyte density for each volume cell of the grid. Forced convection is considered as
flow of electrolyte through the cell generated by electrolyte inlet and outlet. By variation of current density, the limiting
current density can be calculated with a copperion concentration of zero at the cathode surface after reaching the steady-state
conditions in electrolyte. Time dependency of diffusion boundary layer thickness is shown for a chosen cell geometry. Literature
data and measured and calculated values of both quantities are in good agreement. 相似文献
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《Acta Materialia》2004,52(8):2349-2357
Misorientation dependence of grain boundary energy and grain boundary sliding at high temperature were examined in cubic zirconia bicrystals with [1 1 0] symmetric tilt boundaries, which were fabricated by diffusion bonding method from two cubic zirconia single crystals. High-resolution transmission electron microscopy observation revealed that the grain boundary in cubic zirconia bicrystals was clean and atomically sharp without any void or grain boundary amorphous layer. Grain boundary energy of the tilt boundaries was estimated from the dihedral angles on thermal grooved surface measured with atomic force microscope techniques. The misorientation dependence of the grain boundary energy in cubic zirconia bicrystals shows similar tendency to that of fcc metal such as aluminum and copper. Grain boundary sliding associated with intragranular dislocation slip in cubic zirconia bicrystals was observed for all specimens. The amount of the grain boundary sliding showed a good correlation with the misorientation factor of each boundary. Grain boundary migration also took place accompanying with the grain boundary sliding. The observed grain boundary sliding and migration can be explained based on a dislocation mechanism for sliding which is based on the movement of lattice dislocations along the grain boundary by a combination of climb and glide. 相似文献
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提出了具有渐变孔隙正极结构的主动式锂空气液流电池,利用溶液泵驱动电解液循环,结合渐变孔隙正极结构,强化电极内部Li^+和O2扩散和结合能力,减弱电极钝化。基于COMSOL Multiphysics 5.3,建立二维电化学模型,用Darcy定律、Butler-Volmer方程和组分输运公式描述在渐变孔隙正极结构(ε=0.55+αX等)下电极内部电解液流动、正负极电化学反应及电解液中Li^+和O2浓度场分布。由于Li2O2积聚在正极孔隙内,电极比表面积下降,采用Carman-Kozeny方程修正渗透率K。研究渐变孔隙率、压强差、氧气参数、正极厚度及动力学速率系数对该电池放电性能影响。结果表明:在放电电流密度0.1 mA/cm^2,电池比电容量是被动式结构的2.5倍;与ε=0.85-0.1X相比,采用ε=0.55+αX结构的电化学性能较佳;在放电电流密度0.1 mA/cm^2下,正极厚度为500^750μm,电池放电性能较好。 相似文献
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Juan LiNaiqing Zhang Kening Sun Wang SunWei Li 《Journal of Alloys and Compounds》2011,509(17):5388-5393
A facile and environment-friendly method, the so-called vertical deposition (abbreviated as VD) method, is used to prepare thin yttria-stabilized zirconia (YSZ) films (≤5 μm) for solid oxide fuel cells (SOFCs). The YSZ films are self-assembled by VD process based on capillary force. The influence of experimental conditions (e.g. concentration of YSZ dispersion, deposition times, and sintering procedure) on the morphology of the films produced and thereby on the performance of SOFC devices is investigated. The single cell utilizing a 5 μm dense YSZ film as solid electrolyte achieves a high open circuit voltage of 1.05 V which remains stable at 700 °C for 4 h. The peak power density is 0.4 W cm−2 at 800 °C for the phase inversion anode-supported fuel cell composed of an YSZ electrolyte film of 5 μm thick. The VD method developed herein is promising for preparing ultra-thin electrolyte films for SOFCs. 相似文献
17.
Xiaochuan Lu John P. Lemmon Vincent Sprenkle Zhenguo Yang 《JOM Journal of the Minerals, Metals and Materials Society》2010,62(9):31-36
This paper provides a review of materials and designs for sodium-beta alumina battery technology and discusses the challenges
ahead for further technology improvement. Sodium-beta alumina batteries have been extensively developed in recent years and
encouraging progress in performance and cycle life has been achieved. The battery is composed of an anode, typically molten
sodium, and a cathode that can be molten sulfur (Na-S battery) or a transition metal halide incorporated with a liquid phase
secondary electrolyte (e.g., ZEBRA battery). In most cases the electrolyte is a dense solid β″-Al2O3 sodium ion-conducting membrane. The issues prohibiting widespread commercialization of sodium-beta alumina technology are
related to the materials and methods of manufacturing that impact cost, safety, and performance characteristics. 相似文献
18.
Yttria-stabilized zirconia electrolyte coatings for solid oxide fuel cells were deposited by suspension plasma spraying using a range of spray conditions and a variety of substrates, including finely structured porous stainless steel disks and cathode layers on stainless steel supports. Electrolyte permeability values and trends were found to be highly dependent on which substrate was used. The most gas-tight electrolyte coatings were those deposited directly on the porous metal disks. With this substrate, permeability was reduced by increasing the torch power and reducing the stand-off distance to produce dense coating microstructures. On the substrates with cathodes, electrolyte permeability was reduced by increasing the stand-off distance, which reduced the formation of segmentation cracks and regions of aligned and concentrated porosity. The formation mechanisms of the various permeability-related coating features are discussed and strategies for reducing permeability are presented. The dependences of electrolyte deposition efficiency and surface roughness on process conditions and substrate properties are also presented. 相似文献
19.
A thermal spraying-sintering process has been developed for an electrolyte and interconnect layer, which results in improved
gas tightness, a thinner layer, and higher electric conductivity as required for solid oxide fuel cells (SOFCs). The process
is characterized by the heat treatment of composition-controlled plasma-sprayed layers. For the electrolyte, the addition
of MnO2 to zirconia powder is effective for reducing the sintering temperature to obtain gas tightness and for suppressing the reaction
between zirconia and air electrode material. An electrolyte layer of 60 μm thickness with sufficient gas tightness and high ionic conductivity was obtained by this process. For the interconnect,
chromium-rich lanthanum chromite powder, La0.8Ca0.2Cr1.10O3, is optimum for both gas tightness and high electric conductivity of the layer. In addition, a single cell with a 60 μm electrolyte was successfully fabricated using the thermal spraying-sintering process. As a result of an operating test using
O2 and humidified H2 at 1000°C, a power density of 0.73 W/cm2 was obtained. It was demonstrated that the thermal spraying-sintering technology is effective for the fabrication of a thin
gas tight layer for SOFCs. 相似文献
20.
Y. Wang J.-G. Legoux R. Neagu S. Hui B. R. Marple 《Journal of Thermal Spray Technology》2012,21(1):7-15
The use of a liquid feedstock carrier in suspension plasma spray (SPS) permits injection of fine powders, providing the possibility
of producing sprayed coatings that are both thin and dense and have fine microstructures. These characteristics make SPS an
attractive process for depositing highly efficient electrodes and electrolytes for solid oxide fuel cell (SOFC) applications.
In this study, NiO-yttria stabilized zirconia (YSZ) anode and YSZ electrolyte half cells were successfully deposited on porous
Hastelloy X substrates by SPS. The NiO-YSZ anode deposition process was optimized by design of experiment. The YSZ electrolyte
spray process was examined by changing one parameter at a time. The results from the design-of-experiment trials indicated
that the porosity of the as-deposited coatings increased with an increase of suspension feed rate while it decreased with
an increase of total plasma gas flow rate and standoff distance. The deposition rate increased with an increase of total plasma
gas flow rate, suspension feed rate, and standoff distance. The microstructure examination by SEM showed that the NiO and
YSZ phases were homogeneously distributed and that the YSZ phase had a lamellar structure. It was observed that the density
of the YSZ electrolyte layer increased as input power of the plasma torch increased. Electrochemical characterization of the
fabricated cells indicated that an open cell voltage of 0.989 V at 500 °C and a peak power of 0.610 W/cm2 at 750 °C were reached. 相似文献