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Abstract Direct carbon solid oxide fuel cell has garnered increasingly attention due to its high conversion efficiency. However, when a liquid metal is used as the anode, the electrolyte is subjected to hot corrosion by the liquid metal and its oxide. In the present study, both chemical and electrochemical corrosions of Gd 2 O 3 -doped CeO 2 electrolyte by liquid Sb and Sb 2 O 3 are conducted at 750 °C for up to 100 h to simulate the situations occurring in the direct carbon solid oxide fuel cell. The tested specimens are characterized by a scanning electron microscope and an electron probe micro-analyzer. In the case of chemical corrosion, both liquid Sb and Sb 2 O 3 penetrates into grain boundaries of the electrolyte, resulting spallation of grains from the bulk. The depth of liquid Sb penetration is deeper than that of liquid Sb 2 O 3. Electrochemical corrosion of the electrolyte by liquid Sb occurs in the same way as the chemical corrosion at an increased rate promoted by applied current. It is also found that the electrochemical corrosion of the electrolyte by liquid Sb improves the cell performance with the sacrifice of electrolyte. Highlights • The corrosion of GDC electrolyte was studied in two experimental modes. • Both chemical and electrochemical corrosion of GDC electrolyte were happened. • Liquid Sb or Sb 2 O 3 penetrate into GDC grain boundaries, and then grains detached. [ABSTRACT FROM AUTHOR]

Dense bismuth oxides stabilized with lanthanide dopants (δ-Bi 2 O 3 ) are always used as interlayer for thin layer GDC (gadolinia-doped ceria) or YSZ (yttria-stabilized zirconia) electrolyte solid oxide fuel cell to improve the cell performance. Dense ESB (Bi 1.6 Er 0.4 O 3 ) layer preparation needs special equipment or well synthesized nano-sized powders, which is not friendly for large scale and commercial application. In this paper, anode support unsintered cathode cell with porous ESB interlayer is prepared through simple screen print and its electrochemical performance is tested. No matter sintered or not, porous ESB interlayer lowers both the polarization resistance and ohmic resistance, and enhances cell performance, especially for the ohmic resistance of unsintered cells. The cell with ESB porous interlayer and SSC (Sm 0.5 Sr 0.5 CoO 3-δ )-ESB unsintered cathode achieves a peak power density of 1.329 W cm −2 at 700 °C, which is 1.61 times higher than that of the cell without ESB interlayer and 0.93 times higher than that of the sintered cell. However, the durability of porous ESB interlayer enhanced cells is not ideal and it should be improved in further works. [ABSTRACT FROM AUTHOR]

Hydration properties and electrical characteristics of the hightemperature proton conductor La27(W0.85Nb0.15)5O55.5-δ are investigated by means of thermogravimetry, impedance spectroscopy, and the electromotive force (EMF) method as a function of temperature, water vapor, and oxygen partial pressures, as well as isotope exchange measurements in order to elucidate the mechanism and thermodynamics of protons formation and transport. The highest proton conductivity, 1.3 3 10-3 S/cm, is achieved at 700°C in wet O2. Proton selfdiffusion coefficients are estimated from thermogravimetric measurements of hydration and conductivity data. Comparison of the conductivity characteristics between nominally pure and Nb-substituted materials reveals that the ionic conductivity increases and the activation energy decreases with Nb doping. These differences are discussed to reflect changes in the structure promoting ionic transport rather than changing the concentration of defects to any large extent. [ABSTRACT FROM AUTHOR]

Hydration properties and electrical characteristics of the hightemperature proton conductor La27(W0.85Nb0.15)5O55.5-δ are investigated by means of thermogravimetry, impedance spectroscopy, and the electromotive force (EMF) method as a function of temperature, water vapor, and oxygen partial pressures, as well as isotope exchange measurements in order to elucidate the mechanism and thermodynamics of protons formation and transport. The highest proton conductivity, 1.3 3 10-3 S/cm, is achieved at 700°C in wet O2. Proton selfdiffusion coefficients are estimated from thermogravimetric measurements of hydration and conductivity data. Comparison of the conductivity characteristics between nominally pure and Nb-substituted materials reveals that the ionic conductivity increases and the activation energy decreases with Nb doping. These differences are discussed to reflect changes in the structure promoting ionic transport rather than changing the concentration of defects to any large extent. [ABSTRACT FROM AUTHOR]