Novel co-extruded electrolyte–anode hollow fibres for solid oxide fuel cells

Droushiotis, Nicolas; Othman, Mohd Hafiz Dzarfan; Doraswami, Uttam; Wu, Zhentao; Kelsall, G. H.; Li, K.

doi:10.1016/j.elecom.2009.07.022

Cited by 55 publications

(22 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

mentioning

confidence: 99%

“…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).…”

mentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2011

Self Cite

View full text Add to dashboard Cite

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...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

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

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…The resulting micro-tubular proton-conducting SOFC generated a peak power density of 2.54 kW m -2 at 650°C. None of these studies used co-extrusion to produce anode and electrolyte precursors simultaneously, unlike those reported in [2,[10][11][12][13]16].…”

Section: Introductionmentioning

confidence: 98%

“…Most experiments have focused on co-extrusion by phase inversion of NiO-Ce 0.9 Gd 0.1 O 1.95 (CGO) as anode precursors and cerium-gadolinium oxide (CGO) as electrolyte simultaneously [2,[10][11][12][13]16]. The NiO was reduced at 550°C using hydrogen to form Ni anodes, which had greater axial electronic conductivities and better distribution of active Ni than the Ni deposited electrolessly in their electrolyte-supported counterparts, increasing 'triple phase boundary lengths' within the anode.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Micro-tubular solid oxide fuel cells fabricated from hollow fibres

et al. 2011

View full text Add to dashboard Cite

Recent literature is reviewed on a phase inversion process followed by sintering, used to fabricate ceramic hollow fibres (HFs) as precursors to micro-tubular solid oxide fuel cells (MT-SOFCs) with sub-millimetre inner diameters. These aimed to address the outstanding technological and economic issues that have delayed mass production of SOFCs, by increasing electrode surface areas per unit volume relative to planar structures, increasing power outputs per unit volume/mass, facilitating sealing at high temperatures, and decreasing fabrication costs per kW. Some recent experimental results are presented of the effects of temperature, hydrogen flow rate, thermal cycling and time of NiO reduction with H 2 on the subsequent performance of 25 mm long H 2 |Ni-CGO|CGO|LSCF|air MT-SOFCs, incorporating cerium-gadolinium oxide (CGO) electrolyte, nickel anodes and lanthanum strontium cobalt ferrite-CGO (LSCF-CGO) cermet cathodes, designed to operate at 500-600°C. Maximum power densities of 3-5.5 kW m -2 were achieved as the temperature was increased from 550-600°C. The co-extruded MT-SOFCs were resilient to three thermal cycles when heated to operating temperature in ca. 5 min. Their performance was intimately related to the reduction time, suggesting slow conversion of the NiO to Ni within the fabricated anodes. At constant cell voltage, mass transport limited current densities increased from ca. 11 to ca. 13.5 kA m -2 as hydrogen flow rates were increased from 15 to 60 cm 3 min -1 , though had residual NiO in the anode been fully reduced, current densities would have been significantly greater.

show abstract

Effect of electrolyte thickness manipulation on enhancing carbon deposition resistance of methane‐fueled solid oxide fuel cell

et al. 2020

Self Cite

View full text Add to dashboard Cite

Summary Dual‐layer hollow fiber (DLHF) micro‐tubular solid oxide fuel cell (MT‐SOFC) consisting of nickel oxide‐yttria‐stabilized zirconia (NiO‐YSZ) anode/YSZ electrolyte was fabricated via a single‐step phase inversion‐based co‐extrusion/co‐sintering technique in order to investigate the effect of different electrolyte extrusion rates (1‐5 mL min−1) at different sintering temperature (1350°C, 1400°C, and 1450°C) under methane (CH4) condition. The DLHF co‐sintered at 1450°C was chosen as optimum temperature due to the good mechanical strength and gas‐tight property. Meanwhile, 18 to 34 μm of electrolyte thickness was achieved when electrolyte extrusion rate increase from 1 to 5 mL min−1. Power density as high as 0.32 W cm−2 was obtained on the cell with the electrolyte layer of 18 μm in thickness (DLHF1) which is 20% higher than the cell with an electrolyte layer of 34 μm (DLHF5) which was only 0.12 W cm−2 when operated at 850°C. However, DLHF1 had suffered cracking formation that originated from anode site which shortened the stability test duration to only 8 hours of survival under 750°C. While DLHF5 can operate up to 15 hours but an increase in electrolyte thickness had resulted in higher ohmic area‐specific resistance that lowering the power density. Fifty‐seven percent reduction in cell performance was observed under methane condition when compared to the cell that performs using hydrogen gas due to the carbon deposition as proven by Raman spectroscopy and carbon, hydrogen, nitrogen, and sulfur analyzer.

show abstract

Novel co-extruded electrolyte–anode hollow fibres for solid oxide fuel cells

Cited by 55 publications

References 11 publications

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

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

Micro-tubular solid oxide fuel cells fabricated from hollow fibres

Effect of electrolyte thickness manipulation on enhancing carbon deposition resistance of methane‐fueled solid oxide fuel cell

Contact Info

Product

Resources

About