STUDY ON CHARACTERISTICS OF ZrO2-Y2O3-CeO2 SYSTEM AS A SOLID ELECTROLYTE MATERIAL FOR FUEL CELL

• Main Author: KARTADARMA (NIM 13704026), SUPRIHANI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/11462
• Institution: Institut Teknologi Bandung

The use of fossil fuel especially natural oil gives negative effect to environment. So the development of energy alternative to occupy the fossil fuel must be done. One of the most interesting energy alternative is fuel cell which can produce high efficiency electrical energy but safe to environment. Solid Oxide Fuel Cell (SOFC) is a typical fuel cell which utilizes advanced ceramic technology particularly with solid electrolyte. The commonly material used for this kind of electrolyte is zirconia in stabilized using 8% mol of Y2O3 (8YSZ). But this electrolyte has a limitation on its ionic conductivity. 8YSZ can produces high ionic conductivity only in high temperature, so it is necessary to add doping agent, i.e. CeO2 in order to increase its ionic conductivity but in lower temperature.<p>This experiment use zircon opacifier which has to be synthesized first into zirconia. Zirconia powder was obtained from processing of zircon opacifier by product of the concentrate separation at PT Timah, Bangka Island. Zirconia, 8% mol of yttria and ceria powders with different composition were mixed to form ceria doped yttria stabilized zirconia, then followed by compaction at the pressure of 30 kN resulting pellet samples with a diameter of 1.39 cm. The composition of each samples are sample-1 consist of [1% mol of CeO2+8YSZ]; sample-2 [2% mol of CeO2+8YSZ]; sample-3 [4% mol of CeO2+8YSZ] and sample-4 [6% mol of CeO2+8YSZ]. The samples were then sintered on 1400 oC for 1, 2, and 3 hours. From the samples will be analyzed for its characteristic of shrinkage as well as its dominant mass transfer mechanism during sintering, and densification. Beside that the samples obtained after sintering was analyzed for its ionic conductivity using Ultra High Resistance Meter. The calculation of the data will be used to analyze the effect of addition doping ceria in 8YSZ, the effect of sintering time variation and defect reaction to its oxygen ionic conductivity values.<p>From the calculation of diameter shrinkage, it can be known that linear shrinkage from the samples occurred about 14%-20%. The highest linear shrinkage occurred in sample 4Ce1 with a composition of [4% mol of CeO2+8YSZ] which is sintered for an hour with linear shrinkage value is 19.42%. Sintering in sample-3 was observed to be dominated by mass transfer by grain boundary diffusion mechanism, but the mass transfer in other samples could not be determined, due probably to the multi-component mass transfer mechanism. On the other hand the densification of the samples occurred about 20-31%. The highest densification also occurred in sample 4Ce1 with densification value is 31.05%. Sample 4Ce1 also showed a highest ionic conductivity with o value is 4.589x10-7 S/cm. This is caused by the highest densification of sample 4Ce1. The value of o depended on sample"s density, elevated temperature and oxygen ions mobility. By doping of ceria on YSZ can improve the oxygen ionic conductivity because of the higher concentration of oxygen vacancy can make the movement of the oxygen ions easier. <br />