Hamzah Fansuri; Muhammad I. Syafi
Abstract
The aims of this research are to study the sintering technique during the production of BaxSr1-xCo0.8Fe0.2O3-δ (BSCF) membranes and to obtain information about the correlation between Ba 2+ substituent with membrane’s density, hardness and thermal expansion coefficient. BSCF with x = 0.5, ...
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The aims of this research are to study the sintering technique during the production of BaxSr1-xCo0.8Fe0.2O3-δ (BSCF) membranes and to obtain information about the correlation between Ba 2+ substituent with membrane’s density, hardness and thermal expansion coefficient. BSCF with x = 0.5, 0.6 and 0.7 (BSCF 5582, 6482 and 7382) were synthesized by the solid state method. X-ray diffraction analysis revealed that the three oxides possessed a cubic structure with high purity and crystallinity. BSCF membranes were made by dry pressing method from their respective powders which passed through 400 mesh sieves at 1050 o C and 1150 o C. Membranes with high density were obtained from phased sintering technique at 1150 °C. SEM analysis results showed that the surface of the membranes is dense, albeit pores can still be found in the cross section of the membranes. The density of the membranes decreased as the amount of Ba 2+ substituent increases indicated by the increase in pore size. A similar pattern was also found in the membrane hardness which decreased as the amount of Ba 2+ content increased. Thermal expansion coefficient of BSCF 5582 was 18.28 ppm which was the highest one followed by BSCF 6482 and BSCF 7382.
Chen Xia; Muhammad Afzal; Baoyuan Wang; Aslan Soltaninazarlou; Wei Zhang; Yixiao Cai; Bin Zhu
Abstract
Very recently, natural hematite has been developed as an electrolyte candidate for solid oxide fuel cells (SOFCs), because of its considerable ionic conductivity. In this work, to exploit more practical applications of natural hematite, we report a novel mixed-conductive composite made of natural hematite ...
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Very recently, natural hematite has been developed as an electrolyte candidate for solid oxide fuel cells (SOFCs), because of its considerable ionic conductivity. In this work, to exploit more practical applications of natural hematite, we report a novel mixed-conductive composite made of natural hematite (α-Fe2O3) and semiconductor Ni0.8Co0.15Al0.05LiO2-δ (NCAL) to act as membrane layer in a new SOFC technology, electrolyte-layer free fuel cell (EFFC). The Hematite-NCAL composite was synthesized directly from natural hematite and commercial NCAL by solid-state blending and high-temperature calcination. The EFFC were constructed into a sandwich architecture with Hematite-NCAL as the membrane and NCAL pasted-Ni foams as the electrodes. Electrochemical impedance spectra (EIS) and direct current (DC) polarization measurements were carried out to investigate the electrical conductivity of the composite. A high ionic conductivity of 0.16 S cm -1 is achieved by the composite at 600 o C with mass ratios of 7:3 (7Hematite: 3NCAL). When operated at low temperatures, the as-designed fuel cell demonstrated superior power densities of 554 mW cm -2 at 600 o C and 342 mW cm -2 at 500 o C. Considering the competitive cost, abundant resource and eco-friendliness of natural hematite, our findings indicate the Hematite-NCAL can be a highly promising candidate for advanced low-temperature SOFC applications.
