Translated Abstract
Solid oxide fuel cell (SOFC) is a environmental freindly and efficient energy conversion device which can convert chemical energy to electrical energy directly under certain conditions. The operating temperature of traditional SOFC is up to 1000°C, which hinder its commercial application. It is a hot topic recent years that lowering the operation temperature of SOFC through finding suitable materials for its electrolyte and electrode. Some researchers found that BaZr0.1Ce0.7Y0.2O3-δ（BZCY）had high proton conductivity at low-and-medium temperature. At the same time, some other researchers found that samarium-doped cerium oxide(SDC) and carbonate composite electrolytes had better ionic conductivity than SDC. At the purpose of finding suitable materials for SOFC used at low-and-medium temperature, we prepared composite electrolytes by using BZCY and carbonate(mixture of Li2CO3 and Na2CO3) and cathodes by using Li-NiO and BZCY-carbonate composite electrolyte. And then, we tested the electro-chemical properties of the composite electrolytes and composite cathodes.We use solid phase method to synthesize different powder of composite electrolyte and composite electrode. Then we tested the conductivity of composite electrolytes at a range of temperature. Firstly, we found that different treatment for carbonate make different conductivity of composite electrolyte. The composite electrolyte prepared by carbonate without heating and BZCY had higher ionic conductivity. Secondly, the ratio of BZCY and carbonate affected the ionic conductivity of composite electrolyte greatly. When the weight ratio of BZCY and carbonate was 7:3, the ionic conductivity of composite electrolyte was best. Recently, sintering temperature also had great influence on the ionic conductivity of composite electrolyte,which reached the highest level when the sintering temperature was 680°C. The electro-chemical properties of composite cathodes synthesized at different conditions were also researched. Firstly, the ratio of Li-NiO and BZCY-carbonate had great effect on the polarization resistance and conductivity of composite cathodes. When the weight ratio of Li-NiO and BZCY- carbonate was 6:4, the polarization resistance was the lowest and the conductivity was the highest. Secondly, sintering temperature was an important affecting factor for the electro-chemical properties of composite cathode. When the sintering temperature was 600°C, the polarization resistance and conductivity of composite cathode was the best.
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