Fabrication and characterization of micro-tubular cathode-supported SOFC for intermediate temperature operation

Liu, Yu; Hashimoto, Shinji; Nishino, Hanako; Takei, Katsuhito; Mori, M.; Suzuki, Toshio; Funahashi, Yoshihiro

doi:10.1016/j.jpowsour.2007.08.101

Cited by 60 publications

(33 citation statements)

References 23 publications

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“…400 μm thick LSMsupport with a GDC/SSZ bilayer electrolyte. The maximum power densities achieved were 73 mW/cm 2 [8] or cofired [9]. GDC was used in both cases as single electrolyte layer and densified at 1200°C.…”

Section: Introductionmentioning

confidence: 99%

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4+δ: Fabrication and characterisation of dip-coated electrolyte layers

et al. 2009

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a b s t r a c t a r t i c l e i n f o (SSZ) were applied by dip-coating in aqueous suspensions. Electrolyte powders had been attrition-milled to decrease their particle size and densification temperature. The quantity of polyacrylic acid (PAA) as dispersant was optimised by ζ-potential measurements. The densification behaviour was studied by dilatometry and SEM-imaging. A sintering temperature of 1250°C was found to densify GDC whereas SSZlayers remained slightly porous.

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Section: Introductionmentioning

confidence: 99%

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4+δ: Fabrication and characterisation of dip-coated electrolyte layers

et al. 2009

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“…[7] Furthermore, the OCV values obtained in this study are in very good agreement with the OCVs of the most of the CGO micro-tubular SOFCs that were previously reported in literatures. [1,8,[10][11][12][13][14][15][16][17] The power density of the cells varies with the anode structure, as can be seen in Figure 2(a).…”

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confidence: 99%

High‐Performance, Anode‐Supported, Microtubular SOFC Prepared from Single‐Step‐Fabricated, Dual‐Layer Hollow Fibers

et al. 2011

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Micro-tubular solid oxide fuel cells (SOFCs) have been developed in recent years mainly due to their high specific surface area and fast thermal cycling. Previously, the fabrication of micro-tubular SOFC was achieved through multiple-step processes. [1][2][3] A support layer, for example anode-support, is first prepared and pre-sintered to provide mechanical strength to the fuel cell. The electrolyte layer is then deposited and sintered prior to the final coating of cathode layer. Each step involves at least one high temperature heat treatment, making the cell fabrication time-consuming and costly, with unstable control over cell quality. For a more economical fabrication of micro-tubular SOFC with reliability and flexibility in quality control, an advanced dry-jet wet extrusion technique, i.e. a phase-inversion-based coextrusion process, is developed. Using this technique, a dual-layer electrolyte/electrode (either anode or cathode) hollow fibre (HF) can be formed in a single step. Generally, the electrolyte and electrode materials are separately mixed with solvent and polymer binder to form the outer and inner layer spinning suspensions, respectively, before simultaneously co-extruded through a triple-orifice spinneret, passing through an air gap and finally into a non-solvent external coagulation bath. In the mean time, a stream of non-solvent internal coagulant is supplied through the central bore of the spinneret. Thickness of the two layers are largely determined by the design of the spinneret and can be adjusted by the corresponding extrusion rate, while the macrostructure or morphology of the prepared HF precursor can be controlled 1 Submitted to by adjusting co-extrusion parameters such as suspension viscosity, air gap, flow rate of internal coagulant, etc. The obtained dual-layer HF precursor is finally co-sintered once at high temperature as a procedure to remove polymer binder and form bounding between the ceramic materials. In our previous work, [4][5][6] a dual-layer HF support for micro-tubular SOFC, which consists of an electrolyte outer layer of approximately 80 µm supported by an asymmetric anode inner layer with 35 % finger-like voids length, was successfully fabricated using the co-extrusion/co-sintering process. A single cell that obtained after deposition of a multi-layer cathode onto the dual-layer HF produced the maximum power density of 0.59 W cm -2 at 570 o C.[6] Improvement on the structure of the dual-layer HFs was further performed by reducing the electrolyte layer thickness to as thin as 10 µm and the maximum power density of the corresponding cell markedly increased to about 1.11 W cm -2 at 600 o C. [7] Although this result has proved the potential of the dual-layer HF as a promising support for micro-tubular SOFC, the value of powder density was still slightly lower than the ramextruded anode-supported cell with similar electrolyte thickness and highly porous anode (about 1.29 W cm -2 at 600 o C).[8] One of the possible major reasons for the lower power output is the less effectiv...

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“…Micro-tubular design of SOFC offers several advantages over other conventional geometries, such as higher surface area available for electrodes and faster start up time [1]. Currently, the most common techniques used for the fabrication of support of micro-tubular SOFC are cold isostatic pressing [2], extrusion [3][4][5], and gel-casting [6]. A combined phase inversion and sintering method has been recently employed by several research groups investigating ceramic hollow fiber (HF) membranes and their results suggest potential application of this method to SOFC systems [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, limited experimental research has been carried out in developing efficient current collection methods from the inner surface of the micro-tubular SOFC. Up to now, the most commonly used methods are based on inserting expensive silver, gold or platinum wires, layers and/or pastes manually into the lumen (core) of the cell [1,[18][19][20][21] or only at the edges of SOFC tube [1,5,[22][23][24][25][26][27], which can leave most of the anode without current collector. These manual methods usually lead to significant reduction of cell's power output as a consequence of a poor contact and small contacting area between current collector and anode.…”

Section: Introductionmentioning

confidence: 99%

NI/NI‐YSZ Current Collector/Anode Dual Layer Hollow Fibers for Micro‐Tubular Solid Oxide Fuel Cells

et al. 2011

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A co‐extrusion technique was employed to fabricate a novel dual layer NiO/NiO‐YSZ hollow fiber (HF) precursor which was then co‐sintered at 1,400 °C and reduced at 700 °C to form, respectively, a meshed porous inner Ni current collector and outer Ni‐YSZ anode layers for SOFC applications. The inner thin and highly porous “mesh‐like” pure Ni layer of approximately 50 μm in thickness functions as a current collector in micro‐tubular solid oxide fuel cell (SOFC), aiming at highly efficient current collection with low fuel diffusion resistance, while the thicker outer Ni‐YSZ layer of 260 μm acts as an anode, providing also major mechanical strength to the dual‐layer HF. Achieved morphology consisted of short finger‐like voids originating from the inner lumen of the HF, and a sponge‐like structure filling most of the Ni‐YSZ anode layer, which is considered to be suitable macrostructure for anode SOFC system. The electrical conductivity of the meshed porous inner Ni layer is measured to be 77.5 × 105 S m–1. This result is significantly higher than previous reported results on single layer Ni‐YSZ HFs, which performs not only as a catalyst for the oxidation reaction, but also as a current collector. These results highlight the advantages of this novel dual‐layer HF design as a new and highly efficient way of collecting current from the lumen of micro‐tubular SOFC.

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Fabrication and characterization of micro-tubular cathode-supported SOFC for intermediate temperature operation

Cited by 60 publications

References 23 publications

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4+δ: Fabrication and characterisation of dip-coated electrolyte layers

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4+δ: Fabrication and characterisation of dip-coated electrolyte layers

High‐Performance, Anode‐Supported, Microtubular SOFC Prepared from Single‐Step‐Fabricated, Dual‐Layer Hollow Fibers

NI/NI‐YSZ Current Collector/Anode Dual Layer Hollow Fibers for Micro‐Tubular Solid Oxide Fuel Cells

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