Electrode Material of Ceria-Substation Lsccm for Symmetric Solid Oxide Fuel Cells Exposed to H2 Fuel Containing H2S

Abstract

Abstract-10 at.% ceria-substation on A-site for La 0.75 Sr 0.15 Ce 0.1 Cr 0.5 Mn 0.5 (noted as LSCCM) was synthesized by the sol-gel process. The characterizations were done by XRD and SEM. The structures, before and after exposure to 5% H 2 S-5% wet H 2 at 900 ℃, were demonstrated using X-ray diffraction (XRD). And best sulfur tolerance of LSCCM was studied. It also demonstrated that LSCCM had good structural compatibility with electrolyte YSZ. SEM test exhibits a homogeneous distribution of pores. The results of electric performance test prove that the maximal power density was 16.03 mW·cm -2 in 5% H 2 S-5% wet H 2 at 900 . ℃ Index Terms-Symmetrical electrode, ceria-substation, sulfur tolerance, electrochemical performance. I. INTRODUCTIONSymmetric Solid Oxide Fuel Cells (SFCs) [1] as a new concept of Solid Oxide Fuel Cells (SOFC), using the same material as both anode and cathode, has attracted attention because they could reduce such strains greatly, enhance the ease of co-sintering and decrease the fabrication costs derived from the simpler fabrication process considerably and address problems such as reversible sulphur poisoning [1]- [3]. However, there is great challenge for SFCs, replacing the traditional SOFC configuration, due to the choice of electrode material needs to be stricter. For example, in this configuration, the electrode materials should have both good oxidability (as anode) and particular reducibity (as cathode). Furthmore, they should exhibit an adequate degree of porosity and an acceptable electronic conductivity in both oxidising and reducing atmospheres, dimensional stability and chemically and physically compatible with the other fuel cell components, and catalytically active towards oxygen reduction and fuel oxidation without using external reformersDespite the requirements over the materials choice are certainly demanding, the SFC concept has already been proposed and proved using (La,Sr) (LSCCM), ceria-substation at A-site, was prepared and investigated for potential SFC electrodes. The effect of ceria -substation partly in A-site on catalytic activity even in H 2 S-containing fuel would be focused. We researched that LSCCM can be considered as a good electrode material in H 2 S-SFCs mainly due to its better electrochemical performances exposed to H 2 fuel containing H 2 S. 2 in an ethylenediaminetetraacetic acid(EDTA)-ammonia aqueous solution (pH 8-9) with stirring. After added citric acid, ammonia aqueous solution was then added to balance the pH to 7-8. A dark purple solution was obtained, and mixture was stirred further on a magnetic stirrer (IKA)with a certain shear rate at 80 for several hours. After that, the ℃ temperature increased to 200 to form the gel. Then the ℃ resulting gel was heated at 500 to carry out combustion on ℃ a hot plate in the fume hood. After burning out the organic components, the porous ash formed was finely grinding and then calcined under airflow in a high-temperature furnace (NABERTHERM) at 1100 for 5 h to form the black ℃ powder. II. EXPERIMENTAL S...