Fabrication of cathode for solid oxide fuel cells using flame assisted vapour deposition technique

Choy, Kwang Leong; Charojrochkul, Sumittra; Steele, B.C.H.

doi:10.1016/s0167-2738(97)00013-1

Cited by 38 publications

(24 citation statements)

References 4 publications

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“…The particle size of the powders and grain size of the electrodes were determined from the image analysis method using the Image Profession Plus software. The porosity of the electrodes was estimated based on counting the black and gray pixels in the SEM micrographs, which refer to pores and grains, respectively [23]. The electrochemical properties of the electrodes were measured at a CHI 660 C electrochemical work station.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical evaluation of La2NiO4+δ -based composite electrodes screen-printed on Ce0.8Sm0.2O1.9 electrolyte

Zhao

Huang

et al. 2012

J Solid State Electrochem

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La 2 NiO 4+δ , 60 wt.% La 2 NiO 4+δ -40 wt.% La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ , and 60 wt.% La 2 NiO 4+δ -40 wt.% Ce 0.8 Sm 0.2 O 1.9 electrodes were prepared from fine powders on dense Ce 0.8 Sm 0.2 O 1.9 electrolyte substrates by screenprinting technique. Electrochemical impedance spectroscopy and chronopotentiometry techniques were employed to evaluate the electrochemical properties of the composite electrodes in comparison with the La 2 NiO 4+δ electrode. For the three electrodes, main electrode processes were resolved to be charge-transfer at the electrode/electrolyte interface and oxygen exchange on the electrode surface. The contribution of the surface oxygen exchange process was detected to be dominant for the overall electrode polarization. The addition of Ce 0.8 Sm 0.2 O 1.9 into La 2 NiO 4+δ was favorable for the charge transfer process whereas it was undesired for the surface oxygen exchange process. On comparison, adding La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ into La 2 NiO 4+δ was found to benefit both the two electrode processes. The La 2 NiO 4+δ -La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ composite electrode showed optimum electrochemical properties among the three electrodes. At 800°C, the composite electrode achieved a polarization resistance of 0.20 Ω cm 2 , an overpotential of 45 mV at a current density of 200 mA cm −2 , together with an exchange current density of ∼200 mA cm −2 .

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Section: Introductionmentioning

confidence: 99%

Electrochemical evaluation of La2NiO4+δ -based composite electrodes screen-printed on Ce0.8Sm0.2O1.9 electrolyte

Zhao

Huang

et al. 2012

J Solid State Electrochem

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“…The grain size and pore diameter distributions of the electrodes were determined from image analysis using the Image Profession Plus software. The porosity of the electrodes was estimated based on counting black and gray pixels of SEM micrographs, which refer to pores and grains, respectively [23]. The electrochemical impedance spectra of the three-electrode half cells were measured at a potentiostat-galvanostat (SP150, Biologic SAS, France) under zero direct current (DC) bias in the frequency range of 0.01 Hz-100 kHz with an input sinuous signal amplitude of 5 mV.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and electrode properties of La0.6Sr0.4Co0.2Fe0.8O3-δ spin-coated on Ce0.8Sm0.2O2−δ electrolyte

Zhao

Huang

et al. 2010

Ionics

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Fine and uniform La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ powder was synthesized by a glycine-nitrate combustion process. La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ electrodes were prepared on dense Ce 0.8 Sm 0.2 O 2−δ electrolyte substrates using a spin-coating technique by sintering at 900-1,000°C. The electrode properties of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ were investigated by electrochemical impedance spectroscopy and chronopotentiometry techniques with respect to preparation conditions and the resulting microstructures. The results indicate a significant effect of the microstructure on the electrode processes and polarization characteristics. The oxygen adsorption and dissociation process acted as a larger contribution to the overall electrode polarization R p in magnitude compared with the charge transfer process due to relatively low porosity levels of the electrodes. It was detected that the grain size of the electrodes exhibited a crucial role on the electrocatalytic reactivity. At 800°C, the electrode sintered at 950°C attained a polarization resistance of 0.18 Ω cm 2 , an overpotential of 27 mV at a current density of 200 mA cm −2 , and an exchange current density of 308 mA cm −2 .

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“…1.1 shows the schematic of the proposed functionally graded porous LSM cathode which consists of large particles and the columnar pore structure in the outer layer to allow the gas in from the surface. 40 .…”

Section: Research Objectives and Motivationmentioning

confidence: 99%

Microstructure Sensitive Design and Processing in Solid Oxide Electrolyzer Cell

Garmestani¹,

Herring²

2009

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SUMMARYThe aim of this study was to develop an inexpensive manufacturing process for deposition of functionally graded thin films of LSM oxides with porosity graded microstructures for use as IT-SOFCs cathode. The spray pyrolysis method was chosen as a low-temperature processing technique for deposition of porous LSM films onto dense YSZ substrates. The effort was directed toward the optimization of the processing conditions for deposition of high quality LSM films with variety of morphologies in the range of dense to porous microstructures. Results of optimization studies of spray parameters revealed that the substrate surface temperature is the most critical parameter influencing the roughness and morphology, porosity, cracking and crystallinity of the film. Physical and chemical properties of deposited thin films such as porosity, morphology, phase crystallinity and compositional homogeneity have shown to be extensively dependent on the preparation conditions. Detailed analysis of the film formation mechanisms have been discussed in this work. It is suggested that using volatile metal-organic precursors as in CVD would alter the film formation mechanism to MOCVD process in which films of high quality can be processed. Novel electrode microstructures currently include a graded microstructure wherein the large pores are made close to the surface in outer layers for maximum mass transport into the electrode structure and smaller pores and particles close to the electrolyte interface would create maximum number of active reaction sites. Taking the advantage of simplicity of spray pyrolysis technique combined with using metal-organic compounds, the conventional ultrasonic spray system was upgraded to a novel system whereby highly crystalline multiMicrostructure Sensitive Design for Materials in Solid Oxide Electrolyzer Cell, Garmestani vi layered porosity graded LSM cathode with columnar morphology with good electrical conductivity in the range of 500-700 °C was fabricated through a multi-step spray and via optimizing spray parameters. This achievement for the current graded LSM cathode would allow its use in IT-SOFCs.Microstructure Sensitive Design for Materials in Solid Oxide Electrolyzer Cell, Garmestani 7

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Fabrication of cathode for solid oxide fuel cells using flame assisted vapour deposition technique

Cited by 38 publications

References 4 publications

Electrochemical evaluation of La2NiO4+δ -based composite electrodes screen-printed on Ce0.8Sm0.2O1.9 electrolyte

Electrochemical evaluation of La2NiO4+δ -based composite electrodes screen-printed on Ce0.8Sm0.2O1.9 electrolyte

Microstructure and electrode properties of La0.6Sr0.4Co0.2Fe0.8O3-δ spin-coated on Ce0.8Sm0.2O2−δ electrolyte

Microstructure Sensitive Design and Processing in Solid Oxide Electrolyzer Cell

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