La0.6Sr0.4Co0.2Fe0.8O3 cathodes incorporated with Sm0.2Ce0.8O2 by three different methods for solid oxide fuel cells

2018

Fuel Cells

This study compares the electrochemical performance of three perovskite cathode materials, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), Ba0.5Sr0.5Co0.2Fe0.8O3 (BSCF), and Sm0.5Sr0.5Co0.2Fe0.8O3 (SSCF), at different operating temperatures, in order to provide optimal operating condition and performance for different solid oxide fuel cells. Among these three cathodes, BSCF has the highest power density of 39 mW cm−2 at 600 °C, 88 mW cm−2 at 650 °C, and 168 mW cm−2 at 700 °C; LSCF has the highest power density of 263 mW cm−2 at 750 °C and 456 mW cm−2 at 800 °C. The cathode overpotentials have the same trend as the power densities. Activation energies for the total cathode area specific resistance (ASR) are calculated to be 0.44 eV, 0.38 eV, and 0.52 eV for the LSCF, BSCF, and SSCF cathodes, respectively. Stability testing of 100 h shows that the open circuit voltages of the LSCF and BSCF cathodes drop 16.1% and 22.9% at 800 °C, respectively, as well as 15.3% and 11.3% at 600 °C, respectively, indicating that the LSCF cathode is more stable at 800 °C while the BSCF cathode is more stable at 600 °C. This work should provide important guidance for the solid oxide fuel cell designs and properties.

Section: Methodsmentioning

confidence: 99%

Comparison of Different Perovskite Cathodes in Solid Oxide Fuel Cells

2018

Fuel Cells

“…The SDC powder was synthesized by a sol−gel method as reported elsewhere. 32 First, stoichiometric amounts of Sm(NO 3 ) 3 •6H 2 O and Ce(NO 3 ) 3 •6H 2 O (Sm:Ce molar ratio at 2:8) were mixed in a water solution. EDTA and citric acid were used as the chelating agents.…”

Section: Methodsmentioning

confidence: 99%

Co₃O₄/Sm-Doped CeO₂/Co₃O₄ Trilayer Coating on AISI 441 Interconnect for Solid Oxide Fuel Cells

ACS Appl. Mater. Interfaces

2017

Self Cite

In this work, a novel Co/Sm-doped CeO (SDC)/Co trilayer of ∼6 μm is deposited by alternating electrodeposition and electrophoresis and oxidized to a CoO/SDC/CoO trilayer structure. This coating is unique and effective in the following aspects: (1) The area specific resistance of the coated interconnect is more stable and lower than that of the uncoated interconnect after thermal treatment at 800 °C for 400 h. (2) The CoO/SDC/CoO coating layer can effectively inhibit Cr diffusion and evaporation and significantly slow the oxidation rate of the interconnect. (3) The SmSrCoFeO cathode in the electrolyte/cathode/interconnect half-cell retains its initial stoichiometry after 100 h of the thermal treatment. Subsequently, the ohmic resistance R, high frequency polarization resistance R, and low frequency polarization resistance R of the half-cell with the CoO/SDC/CoO coated interconnect are all smaller than those of the half-cell with the bare interconnect. The CoO/SDC/CoO coating layer has great advantages to be used as a protective layer for the metallic interconnect in solid oxide fuel cells to improve cell performance, stability, and durability.

“…This means that the oxygen adsorption and dissociation are almost unchanged by the coating. Our previous work shows that SrCrO 4 forms on the cathode side next to the interconnect when bare interconnects are applied [27,40]. In this study, after 100 hrs of the thermal treatment, the XRD pattern of the SSCF cathode with the Co 0.8 Fe 0.2 oxide coated interconnect is shown in Fig.…”

Section: Interconnect Coating Effects On the Sscf Cathodementioning

confidence: 63%

“…The synthesis of SSCF powders was reported in our previous work [27]. SSCF cathodes were deposited on the YSZ electrolyte by screen printing.…”

Section: Assembly Of Aisi 441/sscf/ysz Tri-layers and Thermal Treatmementioning

confidence: 99%

CoxFe1-x oxide coatings on metallic interconnects for solid oxide fuel cells

Journal of Power Sources

2016

Self Cite

In order to improve the performance of Cr-containing steel as an interconnect material for solid oxide fuel cells, CoFe alloy coatings with Co:Fe ratios of 9:1, 8:2, 7:3, 6:4, and 5:5 are deposited by electrodeposition and then oxidized to Co x Fe 1-x oxide coatings with a thickness of ~6 µm as protective layers on the interconnect. The area specific resistance ofthe coated interconnect increases with the Fe content. Higher Co content oxide coatings are more effective in limiting the growth ofthe chromia scale while all coatingsare effective in inhibiting Cr diffusion and evaporation.With the Co 0.8 Fe 0.2 oxide coated interconnect, the electrochemical performance of the Sm 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 cathode is improved. Only 1.54 atomic percentage of Cr is detected on the surface of the Sm 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 cathode while no Cr is detected 0.66 µm or more into the cathode. Co x Fe 1-x oxide coatings are promising candidates for solid oxide fuel cellinterconnects with the advantage of using existing cathode species for compatibility and performance enhancement.