Search

Abstract: LaCrO3 doped with calcium and cerium on the A-site in the series of La0.9−x Ca x Ce0.1CrO3−δ (LCCC3060, LCCC4050, LCCC5040, LCCC6030 corresponding to x = 0.6, 0.5, 0.4, and 0.3 respectively), is synthesized by a sol–gel combustion method and evaluated as anode material for solid oxide fuel cells (SOFCs). Relatively higher Ca-doping on La in LaCrO3 is found to improve both electronic and ionic conductivity. LCCC compositions have demonstrated good chemical stability in reducing atmospheres. Evaluation of the LCCC material as anode in symmetrical cell configuration shows that the highest Ca-doping composition results in the lowest activation energy and the lowest polarization resistance. La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) electrolyte-supported single cells with LCCC3060 as the anode and La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) as the cathode show that LCCC3060 can be a potential anode material for H2, but not for CH4. [Copyright &y& Elsevier]

Abstract: The effects of reduction and Ga-doping on the physicochemical properties of A-site deficient perovskites Sr0.9Ti0.8−x Ga x Nb0.2O3 (x =0, 0.05, 0.1, 0.15 and 0.2) are reported. With 10% Ga doping, the sample sintered in air and treated at 1400°C in H2 atmosphere exhibits the highest electrical conductivity. It is found that the Ga-doping lowers the sinterability but promotes the reduction of Sr0.9Ti0.8−x Ga x Nb0.2O3. The XRD analysis on the reduced samples suggests that some cations are reduced during the treatment. However, without high temperature pre-reduction, the improvement of Ga-doping is limited and the overall cell performance using Sr0.9Ti0.8−x Ga x Nb0.2O3 as an anode without catalysts is still relatively low. [ABSTRACT FROM AUTHOR]

Abstract: Sr2Fe4/3Mo2/3O6 has been synthesized by a combustion method in air. It shows a single cubic perovskite structure after being reduced in wet H2 at 800°C and demonstrates a metallic conducting behavior in reducing atmospheres at mediate temperatures. Its conductivity value at 800°C in wet H2 (3% H2O) is about 16Scm−1. This material exhibits remarkable electrochemical activity and stability in H2. Without a ceria interlayer, maximum power density (P max) of 547mWcm−2 is achieved at 800°C with wet H2 (3% H2O) as fuel and ambient air as oxidant in the single cell with the configuration of Sr2Fe4/3Mo2/3O6|La0.8Sr0.2Ga0.83Mg0.17O3 (LSGM)| La0.6Sr0.4Co0.2Fe0.8O3 (LSCF). The P max even increases to 595mWcm−2 when the cell is operated at a constant current load at 800°C for additional 15h. This anode material also shows carbon resistance and sulfur tolerance. The P max is about 130mWcm−2 in wet CH4 (3% H2O) and 472mWcm−2 in H2 with 100ppm H2S. The cell performance can be effectively recovered after changing the fuel gas back to H2. [ABSTRACT FROM AUTHOR]

Abstract: Perovskite Sr2Fe1.5Mo0.5O6−δ (SFM) has been successfully prepared by a microwave-assisted combustion method in air and employed as both anode and cathode in symmetrical solid oxide electrolysis cells (SOECs) for hydrogen production for the first time in this work. Influence of cell operating temperature, absolute humidity (AH) as well as applied direct current (DC) on the impedance of single cells with the configuration of SFM|La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM)|SFM has been evaluated. Under open circuit conditions and 60 vol.% AH, the cell polarization resistance, R P is as low as 0.26 Ω cm2 at 900 °C. An electrolysis current of 0.88 A cm−2 and a hydrogen production rate as high as 380 mL cm−2 h have been achieved at 900 °C with an electrolysis voltage of 1.3 V and 60 vol.% AH. Further, the cell has demonstrated good stability in the long-term steam electrolysis test. The results showed that the cell electrolysis performance was even better than that of the reported strontium doped lanthanum manganite (LSM) – yttria stabilized zirconia (YSZ)|YSZ|Ni–YSZ cell, indicating that SFM could be a very promising electrode material for the practical application of SOEC technology. [ABSTRACT FROM AUTHOR]