Solid oxide fuel cell: design, materials, and transport phenomena

Abstract

Fuel cell has been considered as one of the most attractive alternative power generating system due to its number of attractive features such as higher energy conversion efficiency, improved fuel economy, and reduced dependence on conventional fossil fuel, lower emission of unsafe pollution gases, modular design, low vibration and noise. Solid oxide fuel cells (SOFCs) have several advantages compared to other types of fuel cells. SOFCs are less sensitive to composition of fuel and are tolerant to other gas elements including carbon monoxide. It operates at higher temperature range of 700–1000°C, and hence requires no expensive catalysts and allows internal reforming of the hydrocarbon fuels. Some of the major challenges for fuel cell commercialization are the improved cell design; development of materials for electrodes, electrolytes, interconnect/bipolar plates, and seals with improved material properties; improved performance in terms of reactant gas and charge transport through the cell components and reduced overpotential due irreversibilities associated with the reaction kinetics, ohmic loss, mass transfer los; reduced cost of materials and manufacturing; and reliability and durability of the key components. This paper reviews different features of SOFC in terms of operating principles; cell designs and materials for different cell components including electrodes and electrolytes. Critical effects of transport phenomena on the distribution of reactant gas species across the gas channels, gas diffusion layers, and regions adjacent to electrode-electrolyte interfaces are discussed.