Date of Award

5-1-2017

Degree Name

Master of Science

Department

Mechanical Engineering

First Advisor

Koc, Rasit

Abstract

Solid Oxide Fuel Cells (SOFCs) have gained tremendous amount of attraction as an alternate source of electrical energy in the recent decades. The purpose of this research is to develop cathode material for use in solid oxide fuel cells which demonstrates desired properties of high electrical conductivity, excellent chemical stability at high temperatures, desirable thermal expansion characteristics and which can be easily manufactured by sintering in conditions acceptable with other cell components. In the present research, stoichiometry’s of La1-xCax(Fe0.25Co0.25Ni0.25Cr0.25)O3 (x=0,0.1,0.2,0.3) (LCFCNC) were synthesized by using polymerizable precursor method proposed by pechini [1]. The structure and morphology of the powder samples were characterized by X-ray diffraction and SEM. X-ray diffraction results revealed the formation of single phase orthorhombic distorted perovskite structure in all four samples. Prepared powders were made into pellets and were sintered in air at 1400°C for 2 hours. SEM analysis showed the densification of the pellets with the addition of calcium. AC resistance bridge was used to measure the electrical conductivity of the samples in air in the temperature range of 100-900°C. Study of electrical conductivity showed an increasing trend in electrical conductivity with the increase in temperature and the amount of calcium doped on A-site up to 20mol% and the sample with calcium 30mol% on A-site, showed sharp increase in electrical conductivity reaching a maximum of 50 S/cm at 800°C, showing that the present materials can be used as cathode materials in SOFC.

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