| Summary: | 碩士 === 南臺科技大學 === 化學工程與材枓工程系 === 105 === This study focused on the preparation of LSGM/carbonate composite electrolyte which could reduce operating temperature below 600℃. As a proton and oxide co-ion conductor LSGM/carbonate composite electrolyte could enhance the ionic conductivity in the intermediate and low temperature range. This study was divided into three sections. In the first section, the properties of LSGM and LSGM/carbonate composite powders were investigated. Then the morphology and electrochemical performance of LSGM and LSGM/carbonate composite electrolyte with different carbonate content in the second section were investigated. Finally, the effects of adding different Li2O amount sintering aids to the LSGM/LiNaCO370˗Li composite electrolyte were investigated.
The results showed that adding carbonate could enhance the grain growth and reduced the shrinkage of LSGM/carbonate composite electrolyte. Impedance analysis showed that the total resistance of LSGM/carbonate composite electrolyte were significantly smaller than the pure LSGM electrolyte at different operating temperatures range. It were also shown that, the conductivities of LSGM/carbonate composite electrolytes were increased with increasing of the operation temperature and there were two different conductivite mechanism both in low temperature region (< 525℃) and intermediate temperature region (> 525℃). In the intermediate temperature region, the best conductivity of LSGM/LiNa70˗Li 7.5% composite electrolyte reached to 2.73×10-1 S·cm-1 at 650℃; In the low temperature region, the best conductivity of LSGM/LiNa70˗Li 7.5% composite electrolyte reached to 5.82×10-4 S·cm-1 at 450℃.
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