Development of Solid State Electrolyte for Low Temperature Solid Oxide Fuel Cell LT SOFC

Abstract

Fuel cells have become one of the most efficient and environment friendly energy newlineconversion devices. Solid oxide fuel cell (SOFC) is increasingly recognized as highly newlinepromising energy conversion devices in comparison with other fuel cells. Apart from the newlineelectrolyte being solid in state, its chief benefit is its flexibility for fuel, it can convert newlinevariety of fuels to electrical energy. This makes SOFCs a prominent choice, with even newlinehigh efficiency due to the power co-generation advantage. It stands out as the highly newlineefficient fuel cell type with an issue of elevated operating temperature as high as 800 - newline1000 and#8451;. The conventional SOFC used YSZ as the electrolyte material, this led to very newlinehigh operating temperature. This elevated operating temperatures led to critical issues newlinelike interconnect and sealant material selection, chromium poisoning and mane more. newlineAlso, those SOFCs were quite expensive due to the choice of materials which favored newlinehigh operations. This led to a need of an alternative electrolyte material. For obtaining newlinehigh ionic conductivity efforts have been done to improvise its electrolyte properties, newlinesimultaneously reducing the operating temperature. newlineTwo most important aspect of SOFC are: operating temperature and the newlineelectrolyte material. The focus of the thesis is to develop electrolyte materials of rare earth newline(RE) elements doped ceria and to study the correlation between the doping concentration newlinewith the ionic conductivity and density of the electrolyte. The electrolyte s density is an newlineessential factor in determining the effectiveness of the material. This work also newlineconcentrates the relationship between the grain boundaries and their ionic conductivity. newlineThe important points of this work are: newlineand#61623; To develop solid electrolyte for low-temperature SOFC (LT-SOFC) newlineapplications. Typically, ceria-based electrolyte materials having cubic newlinefluorite structure and favoring reduced operating temperature. newlineand#61623; To study the effect of the dopants on the microstructure, oxygen defect newlinegenerations and the ionic conduction of the synthesized materials. newlineiv newlineand#61623; Investigating Sm3+ and Gd3+ doped ceria composites, with optimization of newlinethe dopant concentrations with improved ion conductivity at lower newlinetemperatures. newlineand#61623; Also to examine the novel co-doped ceria composites, to investigate the newlinemorphology, crystal structure and electrical properties of the synthesized. newline newline