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In this work, synthesis and characterization of an anode supported tubular solid oxide fuel cell based on Ba 0.5 Sr 0.5 Ce 0.6 Zr 0.2 Gd 0.1 Y 0.1 O 3-δ (BSCZGY) electrolyte has been investigated. Anode-supported Ni -yttria-stabilized zirconia (YSZ) anode was fabricated via slip casting; BSCZGY electrolyte and BSCZGY -La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) composite cathode were coated on support using dip coating, respectively. The chemical compatibility of fuel cell components at sintering temperatures has been investigated by powder X-ray diffraction, and no severe reactions were detected. Electrochemical examination under air/H 2 + 3 vol. % H 2 O showed superior performance achieving a maximum power density of 1 W/cm 2 at 850 • C, among the best compared to tubular -geometry oxygen conductor solid oxide fuel cells reported earlier and one of the highest reported for a proton conductor electrolyte in literature. Electrochemical impedance spectroscopy was used to examine the electrochemical performance of the full cell at different temperatures, and a detailed analysis was done to distinguish the contribution of ohmic and polarization resistances of the cell. ASR values were 3.47 .cm 2 , 1.81 .cm 2 , 1.23 .cm 2 , and 1.05 .cm 2 at 600, 700, 800, and 850 • C, respectively. Analysis of activation energy associated with charge and mass transfer based on fitting of impedances revealed that concentration polarization is the major contributor to the total resistance. The long-term stability for more than 96 hours of operation under load showed no significant degradation, which demonstrated the steady behavior of the cell. A solid oxide fuel cell (SOFC) is a solid-state electrochemical device which converts the chemical energy stored in the fuel directly into electrical energy resulting in high efficiency which along with low environmental impact, quiet operation, and low maintenance makes SOFC highly suitable for stationary power generation applications. 1Traditional SOFCs employ Ni-YSZ cermet, oxide-ion conducting yttria-stabilized zirconia (YSZ), and lanthanum strontium manganite as the anode, electrolyte and cathode, respectively.2 To reduce the overpotentials associated with these materials, the cell needs to run at elevated temperatures near 1000• C. 3 This negatively affects the choice of available materials mostly for interconnects and sealants and their long-term stability. 4 To reduce the operating temperature of SOFC, one of the alternative is to develop new materials for cell components. Oxide ion conducting electrolytes La 0.9 Sr 0.1 Ga 0.

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