The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitatio...The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitation method with metal-nitrates as starting materials and mixed alkali (NaOH and Na2CO3) as a precipitating agent. The formation process of LSCCF from the precursors was monitored by TG-DSC, and the crystal structure and particles morphology of the precursors which were calcined at 600, 800, 1000 ℃ for 3 h were characterized using XRD, SEM technologies. Compared with the solid state reaction of constituent oxides, when the pH value of the precipitating solution was in the range of 9.1～9.5, the LSCCF powders from the precursors caclined at 800 ℃ for 3 h had high purity, homogeneous and single perovskite phase. The electrical conductivity of the LSCCF samples sintered at 1200 ℃ for 3 h, which was measured as a function of temperatures from 100 to 800 ℃ by DC four-probe method in air, decreased with x from 0.05 to 0.20. The value of electrical conductivity was almost equal because of Ca2+, Sr2+ co-dopant resulting in the 'mix effect' while x=0.10 or 0.15. The electrical conductivity of all doped samples was higher than 100 S·cm-1 at intermediate temperatures from 500 to 800 ℃, and there was good compatibility between the LSCCF cathode and Ce0.8Sm0.2O2 electrolyte.展开更多
La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning el...La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that single-phased perovskite-type oxide powders with small particle size were obtained by the process, and the compositions of the productions agreed with the designed molar ratio. The electronic conductivity and ionic conductivity of La0.8Sr0.2Co1-yFeyO3-δ were investigated by DC four-terminal method and AC impedance spectroscopy, respectively. The electronic conductivity of La0.8Sr0.2Co1-yFeyO3-δ is approximately 2～4 orders of magnitude higher than the ionic conductivity. It was confirmed that the conductivities of the materials were strongly influenced by the composition anions, temperature and sample preparing process.展开更多
La_ 1-xSr_xGa_ 1-yMg_yO_ 3-δ(LSGM)electrolyte material was synthesized by solid-state reaction method. The microstructure characteristics were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), and...La_ 1-xSr_xGa_ 1-yMg_yO_ 3-δ(LSGM)electrolyte material was synthesized by solid-state reaction method. The microstructure characteristics were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), and energy dispersive spectroscopy (EDS). XRD patterns indicate that perovskite phase began to form when the mixed materials were sintered at 1000 ℃, and the material has a pure LSGM perovskite phase when the mixed materials were sintered at 1450 ℃ in air for 24 h. No chemical reaction between LSGM electrolyte material and La_ 1-xSr_xMn_ 1-yCr_yO_ 3-δ(LSMC) anode material or La_ 1-xSr_xFe_ 1-yCo_yO_ 3-δ (LSFC) cathode material was detected after the mixed materials consisting of LSGM and LSMC or LSFC was sintered at 1200 ℃ in air for 15 h respectively, which shows that LSGM electrolyte material has excellent chemical compatibility with LSMC anode and LSFC cathode materials. According to SEM, LSMC anode film and cathode composite film of LSFC and LSMC prepared using direct painting method by sintering at 1150 ℃ are both porous and well cohered on LSGM electrolyte substrate.展开更多
基金the National High-Tech Development Plan (2006AA05Z417)the Natural Science Foundation of Lia-oning Province (20062145)the Education department of Liaoning Province (05L073)
文摘The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitation method with metal-nitrates as starting materials and mixed alkali (NaOH and Na2CO3) as a precipitating agent. The formation process of LSCCF from the precursors was monitored by TG-DSC, and the crystal structure and particles morphology of the precursors which were calcined at 600, 800, 1000 ℃ for 3 h were characterized using XRD, SEM technologies. Compared with the solid state reaction of constituent oxides, when the pH value of the precipitating solution was in the range of 9.1～9.5, the LSCCF powders from the precursors caclined at 800 ℃ for 3 h had high purity, homogeneous and single perovskite phase. The electrical conductivity of the LSCCF samples sintered at 1200 ℃ for 3 h, which was measured as a function of temperatures from 100 to 800 ℃ by DC four-probe method in air, decreased with x from 0.05 to 0.20. The value of electrical conductivity was almost equal because of Ca2+, Sr2+ co-dopant resulting in the 'mix effect' while x=0.10 or 0.15. The electrical conductivity of all doped samples was higher than 100 S·cm-1 at intermediate temperatures from 500 to 800 ℃, and there was good compatibility between the LSCCF cathode and Ce0.8Sm0.2O2 electrolyte.
基金the National Natural Science Foundation of China (50204007)the Talent Foundation of Yunnan Province (2005PY01-33)Programfor New Century Excellent Talents in University (NCET-07-0387)
文摘La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that single-phased perovskite-type oxide powders with small particle size were obtained by the process, and the compositions of the productions agreed with the designed molar ratio. The electronic conductivity and ionic conductivity of La0.8Sr0.2Co1-yFeyO3-δ were investigated by DC four-terminal method and AC impedance spectroscopy, respectively. The electronic conductivity of La0.8Sr0.2Co1-yFeyO3-δ is approximately 2～4 orders of magnitude higher than the ionic conductivity. It was confirmed that the conductivities of the materials were strongly influenced by the composition anions, temperature and sample preparing process.
文摘La_ 1-xSr_xGa_ 1-yMg_yO_ 3-δ(LSGM)electrolyte material was synthesized by solid-state reaction method. The microstructure characteristics were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), and energy dispersive spectroscopy (EDS). XRD patterns indicate that perovskite phase began to form when the mixed materials were sintered at 1000 ℃, and the material has a pure LSGM perovskite phase when the mixed materials were sintered at 1450 ℃ in air for 24 h. No chemical reaction between LSGM electrolyte material and La_ 1-xSr_xMn_ 1-yCr_yO_ 3-δ(LSMC) anode material or La_ 1-xSr_xFe_ 1-yCo_yO_ 3-δ (LSFC) cathode material was detected after the mixed materials consisting of LSGM and LSMC or LSFC was sintered at 1200 ℃ in air for 15 h respectively, which shows that LSGM electrolyte material has excellent chemical compatibility with LSMC anode and LSFC cathode materials. According to SEM, LSMC anode film and cathode composite film of LSFC and LSMC prepared using direct painting method by sintering at 1150 ℃ are both porous and well cohered on LSGM electrolyte substrate.
