Electrochemical Characteristics of La_0.65Sr_0.3 MnO₃ and La_0.8Sr_0.2MnO₃ Nanoceramic Cathode Powders for Intermediate Temperature Solid Oxide Fuel Cell (SOFC) Application

摘要

In the present investigation, La0.65Sr0.3MnO3 (LSM-1) and La0.8Sr0.2MnO3 (LSM-2) nanoceramic powders were prepared by the citrate-nitrate route of auto-combustion with citrate to nitrate (c) ratio : 0.50 to assess the effect of these cathode powders on the performance of single SOFC cells. The prepared powders were calcined at 900 oC for 4hrs to remove carboneous residues and characterized them using SEM / EDS, XRD, TGA techniques. The electrochemical characterization of LSM cathode powders were carried out by coating these powders (as cathode functional layer CFL-Bottom and current collector layer CL- Top) using screen printing on the SOFC half cells (NiO-YSZ+YSZ) procured from CGCRI, Kolkata, o India with a cell size of 36 mm dia x1.6 mm. These cells were tested with H2-O2 at 700-800 C with the flow rates of 1.2-1.8 L min-1 of hydrogen and 0.4-0.6 L min-1 of oxygen. The current density and powder density values obtained for SOFC single cells were 0.85 A cm-2 (at 0.7 V) and 0.58 W cm-2 at 800 oC with 1.8 L min-1 hydrogen and 0.60 L min-1 oxygen. The area surface resistance (ASR) values obtained were ~0.52-0.58 ? cm2 at 0.7 V at 800 oC.