The Electrochemical Role of Mixed Valence Manganite for Fuel Cells

Abstract

In this era renewable energy sources are becoming more important. They will play and anticipate a more vital role in near future to avoid atmosphere changes. In this context, fuel cells have gained much attention due to their high conversion efficiency when contrast with conventional energy conversion system. Among all the fuel cells, solid oxide fuel cell (SOFC) is one of the best sources for energy conversion technologies along with low toxic emission, pollution, fuel flexibility, and cost effective materials characteristics. However, there are still some complications that need to be addressed; one of the significant challenges, activity of SOFC at low temperature is decreased because of interfacial polarization obstructions and also oxygen reduction reaction (ORR). Thus to improve the activity and ORR, Strontium substituted lanthanum Manganite La1-xSrxMnO3 perovskite type cathode materials is synthesized. The prepared materials are Strontium substituted lanthanum Manganite (La1-xSrxMnO3) (LSM)) where x=0, 0.2, 0.4, 0.6, 0.8, 1.0 All samples are prepared by sol gel method. The functionalities of cathode materials (La1-xSrxMnO3) (LSM)) is investigated in this research. Prominent bands at peak positions 310, 456, 643, 990 cm−1 wavelengths are observed through Raman spectra of LSM cathodes, analogous to Mn-O-Mn bonds typical stretching, asymmetric stretching vibrations for Sr-O band. The prominent peaks at 650, 855, 1052cm-1 wavelengths observed through FTIR Analysis, these peaks attributed to stretching vibration of La-O bond, V1mode of carbonate ion, symmetric vibration of Sr-O bond. The band gap energy of material has been calculated 4.18 eV, 4.2 eV, 4.19 eV and 4.21 eV of La1Mn1O3, La0.8Sr0.2Mn1, La0.6Sr0.4Mn1 and La0.4Sr0.6Mn1respectively. These show that the band gap increases with the increase of the Sr2+ions concentration. DC Conductivity measurements of LSM cathode samples are evaluated by four point probe method. The La0.8Sr0.2Mn1O3–δ (LSM)has maximum conductivity of 0.726 Scm-1 at 600 °C .The effects of synthesized LSM materials on performance for Solid Oxide Fuel Cell (SOFC) cathode were studied. The results indicate that developed LSM materials are good cathode for SOFC as they have adequate electrocatalytic properties and good chemical stability.