Recent developments in solid oxide fuel cell technology – a review

169-176This review presents development of low temperature solid oxide fuel cells (SOFC), which with high efficiency and high environmental performance have shown excellent potential as a future source of energy for vehicles and homes. Gd2O3 and Sm2O3 doped ceria based nanomaterials were developed world wide, as alternate electrolyte materials for SOFCs working at reduced temperature (700°C) since, state-of- art YSZ based electrolytes undergo interfacial reactions with adjoining cell components at operating temperature of SOFC after prolonged operation. Novel ceramic composite materials are reported as alternate electrode components of reduced temperature SOFC. Iron based alloys are developed as current collectors for low temperature SOFC applications

Preparation of zirconia thin films by tape casting technique as electrolyte material for solid oxide fuel cells

58-64The effect of solvents ethyl methyl ketone (MEK), toluene, xylene and ethanol on the properties of thin films of zirconia prepared by the tape casting technique is reported here. It has been found that preparation of the slurry for tape casting plays an important role in controlling the textural properties of the membranes. The rheological features of the cast tapes are satisfactorily related to the solvent ratio. The toluene + xylene solvent system has been found to provide fine casting and sintering. The physical characteristics of the green tapes like thickness, density and weight losses during sintering have also been measured. The rate of heating is determined by TGA analysis of the green tapes. The role of solvents in controlling the properties of tape cast zirconia membranes is also described.</span

Preparation, characterization and sintering behaviour of Sr doped PbZrO₃ powders by self-propagating combustion method

270-275The Sr doped PbZrO₃ (Pb1-xSrxZrO3 ; x=0, 0.05, 0.10, 0.15 and 0.20) ceramics have been prepared by glycine-nitrate self-propagating combustion technique. The ceramic powders have been heat treated at 800°C for 6 h in order to get phase pure compounds. The prepared powders are characterized by XRD, density and BET surface area measurements. The XRD patterns obtained on these powders show the formation of pure orthorhombic phase of PbZrO₃ without any impurities. Thin sections of circular components of these powders, made by uniaxial compression, are subjected to annealing at different temperatures in the range 900-1100°C for 2 h in order to throw light on their sintering behaviour. The surface morphology of the sintered components are studied by SEM

Synthesis and characterization of LaCoO₃ based cathode and its chemical compatibility with CeO₂ based electrolytes for intermediate temperature solid oxide fuel cell (ITSOFC)

154-160The use of alternate cathode materials with improved performance and without any chemical reaction with adjoining electrolyte is required for a reduction in operating temperature of SOFC from 1273 K to about 1073 K (ITSOFC). Cobalt containing perovskite oxides such as LaCoO₃ tend to exhibit a higher ionic conductivity due to a greater concentration of oxygen vacancies than other perovskite oxides. The mixed ionic and electronic conducting cathode of the La₁₋xSrxCoO₃₋δ systems has shown the lowest cathodic overpotential for an SOFC air electrode. In this research work, fine powders of La₀․₇₀Sr₀․₃₀CoO₃₋δ (LSC) cathode and Ce₀․₉₀Gd₀․₁₀O₂₋δ (GDC) and Ce₀․₈₀Sm₀․₂₀O₂₋δ (SDC) are synthesized by glycine nitrate combustion synthesis and systematically characterized by XRD and particle characteristics. The electrical properties of LSC cathode and GDC and SDC electrolytes are also studied. But, the crucial requirement for applicability of LSC cathode is its chemical compatibility in conjunction with the alternate solid electrolytes, GDC and SDC without any phase formation. The XRD studies showed no reaction products when the La₀․₇₀Sr₀․₃₀CoO₃₋δ cathode is mixed and calcined with GDC and SDC electrolyte at 1573 K. Hence, the LSC cathode may be combined with CeO₂ based electrolytes in ITSOFC application