Impact of Ternary Carbonate Composition on the Morphology of the Carbon/Carbonate Slurry and Continuous Power Generation by Direct Carbon Fuel Cells

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• 作者：Hirotatsu Watanabe ; Akihiro Kimura ; Ken Okazaki
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：March 17, 2016
• 年：2016
• 卷：30
• 期：3
• 页码：1835-1840
• 全文大小：429K
• ISSN：1520-5029

文摘

This study investigated the impact of ternary carbonate composition (Li₂CO₃/Na₂CO₃/K₂CO₃) on the morphology of the carbon/carbonate slurry and the continuous power generation by direct carbon fuel cells (DCFCs). Carbon/carbonate mixtures were melted to form a slurry at 1073 K. After cooling, the morphology of the solidified slurries was observed at the macro and micro scales. Notable differences were found in the morphology when the carbonate composition was changed. The solidified slurry surface was smooth, with surface carbon particles partly embedded in the carbonate, at Li/Na/K = 12.2/25/62.8 mol %, whereas the slurry surface was irregular, with carbon particles on the surface not embedded in the carbonate at Li/Na/K = 12.2/45/42.8 mol %. This suggested that the carbon particles were well-wetted in the former composition but not in the latter. It was also shown that wetting of the carbon particles was improved by decreasing the mole fraction of Na₂CO₃, which lowered the surface tension of the molten carbonate. The DCFC experiment was conducted in constant current mode (20 mA/cm²) at 1073 K. Continuous power generation was successfully achieved when the carbon was well-wetted. It was shown that the ternary carbonate composition determined the degree of carbon wetting, which, in turn, had a significant impact on the continuous power generation capacity of the DCFC.