Ceramic nanocomposites for solid oxide fuel cells

Abstract

Solid oxide fuel cells (SOFCs) are considered as prospective technology for direct conversion of the energy of chemical fuels into electricity. The development of highly efficient SOFC capable to operate in a range of operational temperature with various fuels, however, needs improvements in the microstructural and physical properties of the cell individual parts including electrodes, electrolytes, and current collectors. It is well understood that electrochemical function of the SOFC individual parts strongly depend on microstructural properties including porosity and pore-size distribution, particle size and size distribution, composition and spatial distribution of the constituent phases, and the length of the so-called triple-phase boundaries (TPBs) in the electrodes. Therefore, performing a control over the particle size and shape of the powders (the nanocomposite precursors) used for fabrication of SOFCs as well as controlling the other processing parameters (such as sintering temperature, shrinkage, ceramic to pore-former loading ratio) offer a capability to fabricate both SOFCs with desired electrochemical, mechanical, and thermal performance. Synthesis of nanomaterial has significantly considered as an important and hot field because it offers fast redox reactions, high specific surface areas, and shortened diffusion paths in the solid phase. Reviewing the literature in the past few years shows that optimizing the microstructural properties of SOFC through combination of advanced nanostructured materials in order to improve the electrochemical performance of the cell has still remained as a significant challenge in developing efficient SOFCs. In this chapter we review the articles in the field of synthesis and application of nanocomposite material for SOFCs and present some significant contributions from many research groups who are working in this area. The SOFC nanocomposite material in this chapter is mainly classified into three categories electrolyte, anode and cathode that are followed by two operational ranges of temperature including high and low temperature.