Development of Lanthanide Incorporated Strontium Cobalt Cathode for Energy Conversion Devices

Abstract

In the modern age of science and technology every system of manual work is transferring to machines to run the these machines energy is required, so the need of time is motivating researchers to enhance their activities in the field of renewable energy production devices which will be able to produce more energy at very low cost. In this regard fuel cell got higher attraction of investigation due to its higher efficiency, environmentally friendly nature, and low cost. Solid oxide fuel cell (SOFC) is an extremely encouraging class of fuel cells. SOFC consists of electrolyte sandwiched between anode and cathode. In this research work, lanthanide based strontium cobalt oxide cathode materials are prepared by sol-gel method and their properties are characterized for the cathode functioning of solid oxide fuel cell (SOFC). The synthesized materials are Sr1Co0.8La0.2 (SCL), Sr1Co0.8Ce0.2 (SCC) and Sr1Co0.8Gd0.2 (SCG). These materials are investigated by various characterization X-ray’s diffraction (XRD), Fourier Transformation Infrared Spectroscopy (FTIR), Raman Spectroscopy, DC-conductivity by four probe methods. XRD characterization is used to conform the chemical composition, type of crystal structure and crystallite size. In the prepared materials Sr1Co0.8La0.2 (SCL) have the least crystallite size which is 19.8 nm. This material showed the best value for conductivity as the crystallite size is inversely proportional to the conductivity of the material. FTIR technique is used to study the chemical composition and its bounding. Existence of C-H, C-C, C=C, O-H either of bending or stretching nature is obtained against the wave number in each sample. In Sr1Co0.8La0.2 (SCL) peaks are found at 853 cm-1,859 cm-1 and 1426 cm-1 which are corresponding to Sr-O, La-O and Co-O respectively. In Sr1Co0.8Ce0.2 (SCC) peaks are found at 703 cm-1, 988 cm-1, 1433 cm-1, 1695 cm-1 and 1746 cm-1 which are attributed to Sr-O, Ce-O,CO-O, Ce=Ce and Ce=O respectively. In Sr1Co0.8Gd0.2 (SCG) peaks are observed at 856 cm-1, 950 cm-1 and 1441 cm-1 which belong to Sr-O, Gd-O and O=Co respectively. For Sr1Co0.8La0.2 (SCL) peaks are found at 157 cm-1, 525 cm-1, 957 cm-1 and 1363cm-1. The peaks at 157 cm-1 and 525 cm−1 wavelengths are analogous to O-B-O typical vibrations. The peak at 957 cm−1 wavelength correspond to B-O bonds stretching vibrations. For Sr1Co0.8Ce0.2 (SCC) peaks are found at 143 cm-1, 950 cm-1 and 1078 cm-1. The peaks at 143 cm−1 wavelength analogous are to O-B-O typical vibrations. The peaks at 950 cm-1 and 1078 x cm−1 wavelength correspond to B-O bonds stretching vibrations. For Sr1Co0.8Gd0.2 (SCG) peaks are found at 141 cm-1, 296 cm-1,649 cm-1, 939 cm-1, 1086 cm-1 and 1344 cm-1. The peaks at 141 cm-1, 296 cm-1 and 649 cm−1 wavelengths are analogous to O B-O typical vibrations. The peaks at 939 cm-1 and 1086 cm−1 wavelength correspond to B-O bonds stretching vibrations. The prepared cathodes shows strong peaks in the range of 700 cm-1 to 1800 cm-1. The peaks are attributed to C-H, C=O, O-H and C=C which are the main bonds present in oxides base cathodes. The electrical DC conductivity of prepared cathode Sr1Co0.8La0.2 (SCL), Sr1Co0.8Ce0.2 (SCC) and Sr1Co0.8Ce0.2 (SCC) was measured by four probe method in the temperature range of (300-600) oC in the presence of methane as a fuel in air environment. Conductivity is increasing with the increase in temperature. The highest values conductivity of all the prepared materials are obtained at 600 oC. Among all the synthesized materials Sr1Co0.8La0.2 (SCL) is showing the best value of conductivity 10 S cm-1 at 600 oC.