Neodymium-doped ceria ceramics as SOFC solid electrolyteand Related Material Properties

• Main Authors: Sih-Hong Chen, 陳思宏
• Other Authors: Yen-Pei Fu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/98713528364046076671

碩士 === 國立東華大學 === 材料科學與工程學系 === 96 === In this study, properties of solid state electrolyte and related half-cell were investigated. For solid state electrolyte, Ce1-xNdxO2-0.5x (NDC, x= 0.05 , 0.1, 0.15, 0.2, 0.25) electrolyte powders were prepared by Chemical co-precipitation process, and NDC powders were analyzed as absorptivity, Specific Surface Area, and crystalline structure by FT-IR, BET, and XRD technique. Then, NDC sintered pellets were analyzed as crystalline structure, surface morphology, hardness and fracture toughness, ionic conductivity and activation enthalpy by XRD, SEM, microhardness tester, electrochemical impedance spectroscopy (EIS). In this study, Ce0.9Nd0.1O1.95 was observed that the best mechanical properties (The value of hardness is 7.978±0.108 GPa, and fracture toughness is 6.846±0.01694MPa.m1/2), maximum total ionic conductivity, and minimum total activation energy (at 550℃, total ionic conductivity is 5.766×10-3 Scm-1 and total activation energy is 0.818 eV). For this reason, to use Ce0.9Nd0.1O1.95 as the electrolyte-support of half-cell. In the literature, the LaCaNi0.1Co0.9O3 (LCNC) is a high mixed ionic and electronic conductors. Therefore, LCNC as cathode material and LCNC/NDC as complex cathode material. For complex cathode, LCNC cathode powders were prepared by solid state reaction method. Then, LCNC and NDC were mixed to form complex cathode powders, and complex cathode powders were analyzed as crystalline structure, surface morphology by XRD and SEM. Solid electrolyte and complex cathode were made as half-cell by screen printing in this study. For half-cell, the cross-section morphology andelectrochemistry performance as polarization resistances and exchange current density (io) were analyzed by SEM, EIS and overpotential measurement. The half-cell that was composed of pure LCNC cathode and NDC solid state electrolyte had the best properties of oxygen reduction by io of EIS, io of HF, io of LF (at 850℃, io,EIS is 260.7298 mA/cm2, io,HF is 73.887581 mA/cm2, io,LF is 55.10552 mA/cm2 ). I hope this study to provide help in the purpose that develop Alternative energy source.