Low-temperature fuel cells using a composite of redox-stable perovskite oxide La0.7Sr0.3Cr0.5Fe0.5O3-delta and ionic conductor

摘要

A novel solid oxide fuel cell (SOFC) incorporating the semiconductor with the ionic conductor to replace the traditional electrolyte layer with improved performance has been recently reported. In the present work, we found that the redox stable electrode material La0.7Sr0.3Cr0.5Fe0.5O3-delta(LSCrF) can be considered as a good candidate for such configuration, electrolyte layer-free fuel cells (EFFCs), due to its high ionic and electronic conductivities, excellent catalytic activity and good chemical stability. EFFCs based on the composite of perovskite oxide LSCrF and ionic conductor Ce0.8Sm0.2O2-delta (SDC) offered promising performances, i.e., 1059 mW cm(-2) at 550 degrees C without any electronic short circuiting problem. It even exhibited a highly promising result of 553 mW cm(-2) at 470 degrees C in further low-temperature operation. These high performances can be attributed to the improved conductivity, more triple-phase boundaries (TPB) and accelerated oxygen reduction reaction (ORR) of LSCrF-SDC composite. The influence of the weight ratio between LSCrF and SDC on the EFFC electrochemical performance was investigated. This new discovery indicates a great potential for exploring multifunctional perovskites for the new SOFC technologies. (C) 2017 Elsevier B.V. All rights reserved.