Electrochemical and thermal properties of SmBa0.5Sr0.5CO2O5+delta cathode impregnated with Ce0.8Sm0.2O1.9 nanoparticles for intermediate-temperature solid oxide fuel cells

摘要

SmBa0.5Sr0.5CO2O5+delta (SBSC55) impregnated with nano-sized Ce(0.8)Sm(0.2)0O(1.9) (SDC) powder has been investigated as a candidate cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The cathode chemical compatibility with electrolyte, thermal expansion behavior, and electrochemical performance are investigated. For compatibility, a good chemical compatibility between SBSC55 and SDC electrolyte is still kept at 1100 degrees C in air. For thermal dilation curve, it could be divided into two regions, one is the low temperature region (100-265 degrees C); the other is the high temperature region (265-850 degrees C). In the low temperature region (100-265 degrees C), a TEC value is about 17.0 x 10(-6) K-1 and an increase in slope in the higher temperatures region (265-800 degrees C), in which a TEC value is around 21.1 x 10(-6) K-1. There is an inflection region ranged from 225 to 330 degrees C in the curve of d(delta L/L)/dT vs. temperature. The peak inflection point located about 265 degrees C is associated to the initial temperature for the loss of lattice oxygen and the formation of oxygen vacancies. For electrochemical properties, the polarization resistances (R-P) significantly reduced from 4.17 Omega cm(2) of pure SBSC55 to 1.28 Omega cm(2) of 0.65 mg cm(-2) of SDC-impregnated SBSC55 at 600 degrees C. The single cell performance of SBSC55 I SDCINi-SDC loaded with 0.65 mg cm(-2) SDC exhibited the optimum power density of 823 mW cm(-2) at operating temperature of 800 degrees C. Based on above-mentioned properties, SBSC55 impregnated with an appropriate SDC is a potential cathode for IT-SOFCs. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.