Effect of Mg/Al Ratio on Hydroxide Ion Conductivity for Mg–Al Layered Double Hydroxide and Application to Direct Ethanol Fuel Cells
Effect of Mg/Al Ratio on Hydroxide Ion Conductivity for Mg–Al Layered Double Hydroxide and Application to Direct Ethanol Fuel Cells
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DOI：
10.1149/2.007204jes
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发表时间：
2012
影响因子：
3.9
通讯作者：
K. Tadanaga;Y. Furukawa;A. Hayashi;M. Tatsumisago
中科院分区：
文献类型：
--
作者：
K. Tadanaga;Y. Furukawa;A. Hayashi;M. Tatsumisago
采用共沉淀法制备了Mg/Al= 2，3和4的碳酸根插层Mg-Al水滑石（LDHs），考察了Mg/Al比对LDHs离子电导率的影响。结果表明，Mg/Al比影响Mg-Al CO 3 2− LDH的离子电导率。Mg/Al= 2和3的Mg-Al CO 3 2− LDH在室温和80%相对湿度下的电导率几乎相同，约为1× 10− 3 S cm− 1，而Mg/Al= 4的LDH的电导率低一个数量级。热分析表明，与Mg/Al= 4相比，Mg/Al= 2或3的Mg-Al CO 3 2− LDH在更高的温度下保持层间水分子，这表明层间水分子被强烈地保持在层间。在Mg/Al= 2和3的Mg-Al CO 3 2− LDH中，强层间水分子被假定为贡献了高离子电导率。以Mg/AlCO 32 − LDH为氢氧化物导电电解质的碱性直接乙醇燃料电池可以正常工作，且Mg/Al比越小，Mg-AlCO 32 − LDH的输出功率越大。
Mg–Al layered double hydroxides (LDHs) intercalated with carbonate anions were prepared by the co-precipitation process with Mg/Al= 2, 3 and 4, and the effect of Mg/Al ratio on the ionic conductivity was examined. It is shown that the Mg/Al ratio influences ionic conductivities of Mg–Al CO 3 2− LDH. The conductivity of Mg-Al CO 3 2− LDH with Mg/Al= 2 and 3 exhibited almost the same ionic conductivity of about 1× 10− 3 S cm− 1 at room temperature under 80% relative humidity, while that of LDH with Mg/Al= 4 was lower by one order of magnitude. Thermal analyses showed that Mg-Al CO 3 2− LDH with Mg/Al= 2 or 3 keeps interlayer water molecules at higher temperatures compared with Mg/Al= 4, suggesting that the interlayer water molecules are strongly held in the interlayer. The strongly held interlayer water molecules are assumed to contribute the high ionic conductivity in Mg-Al CO 3 2− LDH with Mg/Al= 2 and 3. The alkaline type direct ethanol fuel cells using Mg/Al CO 3 2− LDHs as hydroxide conducting electrolyte were confirmed to operate, and larger power was obtained in Mg-Al CO 3 2− LDH with smaller Mg/Al ratio.