Investigation of The Role of Dielectric Relaxation in Resulting Superior Conductivities in Oxide Ion Electrolyte for Solid Oxide Fuel Cells

Abstract

Fuel cells are the electrochemical devices capable of continuously converting the chemical energy stored in a fuel such as hydrogen or methane to electricity. Fuel cell technologies can be employed to gradually reduce fossil fuel dependency and environmental impact compared to conventional combustion-based power generation technologies. Solid oxide fuel cells (SOFCs) use ceramic oxide-ion or proton-conducting electrolytes as separators to electrochemically connect the fuel (Hydrogen or Methane) to oxidant (air or oxygen) to produce electricity. SOFC operates at higher temperatures to avoid the ohmic losses generated due to lower ionic conductivities of electrolyte separators. One of the key approaches to lowering the operating temperature of solid oxide fuel cells (SOFCs) is to develop novel electrolyte materials with superior ionic conductivities, thermo-mechanical properties, and low processing temperature compared to the well-known ones perovskite and fluorite based oxide ion conductors. This thesis focuses on the synthesis of oxide-ion conductors and establishing the role of high and#954; dielectric in accelerating the motion of oxide ion vacancies. Novel materials were synthesized employing the solid-state and sol-gel auto combustion method. Samples were characterized structurally (XRD), morphologically (SEM, TEM-EDAX), and thermally (TGA, DSC) thoroughly. Spectroscopy studies (Impedance, Raman, FTIR) were also deliberated to understand the transport properties of the samples. newline