Wet-Chemical Synthesis and Physico / Electro-Chemical Performance Characteristics of Novel Perovskite Cathode Materials for Low-Temperature Solid Oxide Fuel Cells

Abstract

Different perovskite-based materials are proposed as cathode materials for solid oxide fuel cells (SOFCs) working at low temperatures (~600 oC). In this research work, a set of perovskite cathode materials, such as Sm1-xCexCoO3-δ, Sm1-xCexMnO3-δ, Gd1-xCexCoO3-δ andGd1-xCexMnO3-δ (x = 0.1–0.2)were prepared for SOFC applications by co-precipitation method with sodium hydroxide solution as the precipitating agent. The precipitated hydroxides were calcined at 300, 600, 750, 900, and 1100 oC /2 hours in the air using a thermolyne furnace. The calcined powder particles were characterized by XRD, FT-IR, Particle Size, SEM, and EDAX techniques. XRD patterns revealed the presence of orthorhombic primitive phases in the samples. Crystallite sizes of the materials were also determined with XRD method. The presence of M-O bond was confirmed by FT-IR spectroscopy. Particle size analysis proved the presence of samples in the range of 247-976 nm. However, the SEM images revealed the presence of nano-sized particles. The atomic percentage of elements present in the materials was measured by EDAX. Pellets of cathode samples were made and sintered at high temperatures. The conductivity values of the specimens were measured with electrochemical impedance spectroscopy at different temperatures. The cathode specimen, Gd1-xCexCoO3-δ (x=0.1 and 0.2) exhibited better electronic conductivity than other samples. It was found that the prepared cathode samples are stable at moderate temperatures and suitable for Low-Temperature Solid Oxide Fuel Cell (LTSOFC) application.