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    Öğe
    Synthesis of (Bi2O3)0.9-x(Tb4O7)0.1(Sm2O3)x electrolyte for IT-SOFCs
    (Taylor & Francis Inc, 2018) Ermis, Ismail; Sertkol, Murat; Corumlu, Vahit; Dagdemir, Yilmaz; Ari, Mehmet
    In this study (Bi2O3)(0.9-x)(Tb4O7)(0.1)(Sm2O3)(x) ternary solid solutions were synthesized by solid-state synthesis techniques. The products were characterized by means of X-ray powder diffraction, differential thermal analysis/thermal gravimetry, and the four-point probe technique (4PPT). Total electrical conductivity (sigma T) depending on the temperature and doping concentration has been measured by 4PPT. Activation energy of the four samples are calculated by Arrhenius relation. Activation energies of the samples increases with the concentration of dopant Sm2O3. Bi2O3-based ceramic system doped with Sm2O3 and Tb4O7 showed an oxide ionic-type electrical conductivity which is increased with the increasing amount of Sm2O3. The highest conductivity value is found as 3.48x10(-1) S cm(-1) for the (Bi2O3)(0.85)(Tb4O7)(0.1)(Sm2O3)(0.05) ternary system at 850 degrees C.
  • [ X ]
    Öğe
    The phase stability and conductivity of Ho2O3-Gd2O3 co-doped electrolyte for solid oxide fuel cell
    (Springer, 2016) Corumlu, Vahit; Ermis, Ismail; Acer, Semra D.; Cifci, Tugba; Dagdemir, Yilmaz; Ari, Mehmet
    In this study, Bi2O3 ternary system sample materials were synthesized by using solid state reaction method. Two oxides, Ho2O3 and Gd2O3, were used to stabilize the delta (cubic) Bi2O3 phase used as an electrolyte of solid oxide fuel cell applications. The characteristics and electrical properties of these electrolyte samples for solid oxide fuel cells were evaluated by X-ray diffraction (XRD), scanning electron microscope and the four-point probe technique. According to XRD measurements, delta-phase (x = 0.05-0.1, y = 0.05, 0.1, 0.15, 0.2) samples were obtained with a stable structure. The results of the electrical measurements of the (Bi2O3)(1-x-y)(Ho2O3)(x) (Gd2O3) y ternary system show that the electrical conductivity increase with decreasing amount of Gd2O3 molar ratio at a fixed molar ratio of Ho2O3. The value of highest conductivity was found as 2.53 x 10(-1) S cm(-1) for the (Bi2O3)(1-x-y)(Ho2O3)(x)(Gd2O32O3)(y) ternary system (x = 0.05 mol% and y = 0.05 mol%) at 973 K. It was found that activation energy at low temperature varied from 1.10 to 1.29 eV and the activation energy at high temperature varied from 0.61 to 0.70 eV.