Fabrication of Ce0.85Y0.15O2-θ-Sm0.5Sr0.5Co0.9Ni0.1O3-δ composite cathode

• Main Authors: Shu-You Jiang, 江書佑
• Other Authors: Jyung-Dong Lin
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/94588193451759940843

碩士 === 義守大學 === 材料科學與工程學系碩士班 === 99 === This study attempted to replace Co in the Sm0.5Sr0.5CoO3-δ (SSC) with Ni and prepared Sm0.5Sr0.5Co1-xNixO3-δ (SSCN) cathode. In literature, the electrode materials containing Ni usually had better conductivity; on the other hand, the addition of Ni may reduce the TEC value of SSC to match that of electrolytes. We used the Pechini method to synthesize the SSCN with the different Ni contents and explored the relationship between microstructure and conductivity. At first, Ce0.85Y0.15O2-θ (CYO) powders were prepared by urea hydrolysis. Subsequently, CYO powders were added to Sm0.5Sr0.5Co1-xNixO3-δ precursor solution to form yCe0.85Y0.15O2-θ-(1-y) Sm0.5Sr0.5Co1-xNixO3-δ composite powders (y=20, 40, 50, 60wt%). In addition, the influence of CYO particle size on the microstructure and electrical conductivity of CYO-SSCN composite cathodes are further studied in details. The results indicated that the replacement of Co in SSC with Ni can effectively decrease the TEC and slightly lower the electrical conductivity of materials. However, when the addition of Ni was more than 10%, the insulated spinel phases will present and be detrimental to the conductivity of SSCN materials. The conductivity of the CYO-SSCN1 composite cathodes usually showed a maximum value at 600℃. As the calcination temperature CYO increased, the electrical conductivity achieved a maximum value at 900℃ and then decreased. It may be contributed to the change of SSCN1 phase distribution and the decrease of bulk density of CYO-SSCN1 composite cathodes. Alternatively, the thermal expansion coefficient (TEC) value of CYO-SSCN1 increased with the calcination temperature of CYO. Based on the above results, the addition of Ni can reduce the TEC of SSC values and exhibit the higher conductivity of 500S/cm, which is twice that of SSCF. In fact, the composite cathode CYO-SSCN1 usually possesses a lower TEC than SSCN1.