Pencirian Fizikal dan Terma Komposit Seramik Elektrolit SDC-(Li/Na)2CO3

This paper presents the physical and thermal properties of composite electrolytes based on samarium-doped cerium (Ce0.8Sm0.2O1.9, SDC) and carbonates (67 mol% Li2CO3/ 33mol% Na2CO3). SDC–(Li/Na)2CO3 composite is an excellent ionic conductor that is potentially viable for use as an electrolyte material for low temperature solid oxide fuel cells (LT-SOFC). Characterisation of the composite electrolyte includes the morphology, surface area, thermal analysis and porosity of the electrolyte pellets. The fabrication of the SDC–(Li/Na)2CO3 electrolyte composites were achieved in two steps: (1) preparation of the samarium-doped cerium powders by sol-gel and (2) mixing of the samarium-doped cerium with carbonates in various compositions by solid state reaction. The electrolyte pellets were compacted at different pressures (25, 50, 150 and 200 MPa) and sintered at 500, 600, 700 and 800oC. The XRD results demonstrated that the introduction of carbonates did not change the SDC phase structure. FESEM images showed that the carbonate component was amorphous and well distributed in the SDC matrix. The greater the carbonate content in the composite, the smaller the surface area. Thermal analysis indicated that the melting point of the carbonate phase decreased with a reduction of the fraction of carbonate content. The optimum porosity most suitable for LT-SOFC electrolytes, 3.38% and 4.85%, were achieved for samples with carbonate content of 20% (SDC8020) and 30% (SDC7030), respectively. These were for samples sintered at 600oC and cold pressed at 200 MPa.