Pattaraporn Kim-Lohsoontorn

Characterization and Electrochemical Performance of Composite BSCF Cathode for Intermediate-temperature Solid Oxide Fuel Cell

The composite barium strontium cobalt ferrite (BSCF) cathodes were investigated in the intermediate temperature range of solid oxide fuel cells (SOFCs). The characteristics and electrochemical performances of composited BSCF/samarium doped ceria (SDC); BSCF/gadolinium doped ceria (GDC); and BSCF/SDC/GDC were compared to single BSCF cathode. The BSCF used in this study were synthesized using glycine nitrate process and mechanically mixing was used to fabricate a composite cathode. Using a composite form, the thermal expansion coefficient (TEC) could be reduced and BSCF/SDC/GDC exhibited the lowest TEC value at . The electrochemical performance from half cells and single cells exhibited nearly the same trend. All the composite cathodes gave higher electrochemical performance than the single BSCF cathode (0.22 ); however, when two kinds of electrolyte were used (BSCF/SDC/GDC, 0.36), the electrochemical performance was lower than when the BSCF/SDC (0.45 ) or BSCF/GDC (0.45 ) was applied as cathode (, 97%/3% to the anode and ambient air to the cathode).

Modelling of a tubular solid oxide fuel cell with different designs of indirect internal reformer

Abstract The cell performance and temperature gradient of a tubular solid oxide fuel cell with indirect internal reformer (IIR-SOFC) fuelled by natural gas, containing a typical catalytic packed-bed reformer, a catalytic coated wall reformer, a catalytic annular reformer, and a novel catalytic annular-coated wall reformer were investigated with an aim to determine the most efficient internal reformer system. Among the four reformer designs, IIR-SOFC containing an annular-coated wall reformer exhibited the highest performance in terms of cell power density (0.67 W·cm−2) and electrical efficiency (68%) with an acceptable temperature gradient and a moderate pressure drop across the reformer (3.53 × 10−5 kPa). IIR-SOFC with an annular-coated wall reformer was then studied over a range of operating conditions: inlet fuel temperature, operating pressure, steam to carbon (S : C) ratio, gas flow pattern (co-flow and counter-flow pattern), and natural gas compositions. The simulation results showed that the temperature gradient across the reformer could not be decreased using a lower fuel inlet temperature (1223 K–1173 K) and both the power density and electrical efficiency of the cell also decreased by lowering fuel inlet temperature. Operating in higher pressure mode (1–10 bar) improved the temperature gradient and cell performance. Increasing the S : C ratio from 2 : 1 to 4 : 1 could decrease the temperature drop across the reformer but also decrease the cell performance. The average temperature gradient was higher and smoother in IIR-SOFC under a co-flow pattern than that under a counter-flow pattern, leading to lower overpotential and higher cell performance. Natural gas compositions significantly affected the cell performance and temperature gradient. Natural gas containing lower methane content provided smoother temperature gradient in the system but showed lower power density and electrical efficiency.

BaZr0.3Ti0.7O3 Nanoparticles Synthesized by Glycine-Nitrate Autocombustion

BaZr0.3Ti0.7O3 (BZT) nanoparticles were prepared by glycine-nitrate autocombustion method. The effects of synthesis condition and calcination temperature on phase formation and microstructure of the BZT were investigated. XRD and FT-IR study indicated that BZT with cubic perovskite-type structure can be obtained from the synthesis condition using glycine-to-nitrate molar ratio of 2:3 and calcined in air at 1000°C for 4 h. The microstructure examined by SEM and TEM showed that BZT had agglomerate particles consisted of primary spherical nanocrystals with the crystallite sizes of 8–20 nm.