Search

Abstract: The effect of small addition of different sintering aids (MoO3 and WO3) on the electrical properties of Ce0.9Nd0.1O2−δ has been investigated. The (Ce0.9Nd0.1)1−x M x O2−δ (x = 0.0; M = Mo, W, x = 0.01; Ce0.9Nd0.1O2−δ : NDC, (Ce0.9Nd0.1)0.99Mo0.01O2−δ : NDCMo; (Ce0.9Nd0.1)0.99W0.01O2−δ : NDCW) solid solutions were prepared and characterized. The X-ray diffraction patterns indicate that all the samples are single phases with a cubic fluorite structure. Moreover, from the field-emission scanning electron microscopy results, it is found (Ce0.9Nd0.1)0.99M0.01O2−δ (M = Mo, W) sintered at 1300 °C for 15 h have better sinterability than Ce0.9Nd0.1O2−δ . The total conductivity by electrochemical impedance spectroscopy are ranked as: NDCW  > NDCMo  > NDC measured at 700 °C, which is attributed to microstructures. It can be concluded that MoO3 and WO3 are both effective and WO3 seems to be more potential as sintering aids on the optimization of electrical properties for ceria-based electrolytes. [Copyright &y& Elsevier]

Bi-doped La 2- x Bi x Cu 0.5 Mn 1.5 O 6 (LBCM- x , x = 0, 0.1 and 0.2) were synthesized as potential cathode materials for intermediate-temperature solid oxide fuel cells. The effects of 6s 2 lone pair electrons on the electrical and electrochemical properties of LBCMs were investigated. The results reveal that Bi 3+ affects the properties of LBCMs in two ways. First, Bi doping can promotes the formation of oxygen vacancies, which is consistent with the results of first-principles calculations. The formation of oxygen vacancies can increase the amount of Mn 3+ /Mn 4+ pairs for the hopping of electrons and accelerate the oxygen transportation. Second, Bi doping can affect the microstructure of LBCMs and make LBCM-0.1 has the smallest grain size. The dual effects of Bi doping result in the highest electrical conductivity (143.91 Scm −1 ) as well as the lowest polarization resistance (0.101 Ωcm 2 ) of LBCM-0.1 at 850 °C and make it a superior cathode candidate for solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

As a mixed oxygen ionic and electronic conductor, SrFe0.8Mo0.2O3-δ is confirmed to be a good cathode material for intermediate-temperature solid-state fuel cells (IT-SOFCs). The sample of SrFe0.8Mo0.2O3-δ is synthesized by a solid-state reaction method. Pure cubic SrFe0.8Mo0.2O3-δ perovskite, with space group of Pm-3m (no. 221) and lattice parameter a =3.9120(1) Å, is determined via Powder X-ray Rietveld refinements. X-ray photoelectron spectroscopy testifies the existence of mixed oxidation states Fe2+/3+/4+ and Mo5+/6+ in the crystal. Thermogravimetry analysis consistently shows that the SrFe0.8Mo0.2O3-δ begins to the loss of lattice oxygen at about 450°C, which overlaps to the inflection temperature of the electrical conductivity profile. The maximum electrical conductivity obtained is about 50.20Scm−1 at 450°C, and the impedance 0.11 Ω cm2 at 850°C. The performance demonstrates that SrFe0.8Mo0.2O3-δ is a potential candidate as a cathode material for IT-SOFCs. [ABSTRACT FROM AUTHOR]

In order to optimize the electrical properties of co-doped ceria electrolytes, Ce 0.8 Ca 0.15 Sm 0.05 O 2− δ (CCS) sintered at different temperatures (1150 °C, 1200 °C, 1250 °C, 1300 °C and 1350 °C for 8 h) have been prepared and systematically investigated. It is found that among these samples sintered at different conditions, the electrical conductivity ( σ ) measured at 800 °C can be ranked as: CCS 1250 °C : σ CCS 1250 ° C 800 ° C = 2.38 × 10 −2 S cm −1 > CCS 1200 °C : σ CCS 1200 ° C 800 ° C = 1.81 × 10 −2 S cm −1 > CCS 1150 °C : σ CCS 1150 ° C 800 ° C = 1.50 × 10 −2 S cm −1 > CCS 1300 °C : σ CCS 1300 ° C 800 ° C = 1.26 × 10 −2 S cm −1 > CCS 1350 °C : σ CCS 1350 ° C 800 ° C = 0.68 × 10 −2 S cm −1 . The electrical conductivity of CCS increases with the increase of sintering temperatures, and the 1250 °C-sintered sample presents the highest conductivity because of the best microstructures. However, the electrical conductivity of CCS decreases when the sintering temperatures goes beyond 1250 °C. We attribute this to the phase instability. It reveals that microstructures and the phase stability have important effects on the optimization of electrical properties for the co-doped ceria electrolytes. [ABSTRACT FROM AUTHOR]

Abstract: In order to optimize the electrical properties of co-doped ceria electrolytes, Ce0.8Ca0.15Sm0.05O2−δ (CCS) sintered at different temperatures (1150 °C, 1200 °C, 1250 °C, 1300 °C and 1350 °C for 8 h) have been prepared and systematically investigated. It is found that among these samples sintered at different conditions, the electrical conductivity (σ) measured at 800 °C can be ranked as: CCS1250 °C:  = 2.38 × 10−2 S cm−1 > CCS1200 °C:  = 1.81 × 10−2 S cm−1 > CCS1150 °C:  = 1.50 × 10−2 S cm−1 > CCS1300 °C:  = 1.26 × 10−2 S cm−1 > CCS1350 °C:  = 0.68 × 10−2 S cm−1. The electrical conductivity of CCS increases with the increase of sintering temperatures, and the 1250 °C-sintered sample presents the highest conductivity because of the best microstructures. However, the electrical conductivity of CCS decreases when the sintering temperatures goes beyond 1250 °C. We attribute this to the phase instability. It reveals that microstructures and the phase stability have important effects on the optimization of electrical properties for the co-doped ceria electrolytes. [Copyright &y& Elsevier]