High-efficiency intermediate temperature solid oxide electrolyzer cells for the conversion of carbon dioxide to fuels
High-efficiency intermediate temperature solid oxide electrolyzer cells for the conversion of carbon dioxide to fuels
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DOI：
10.1016/j.jpowsour.2013.11.047
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发表时间：
2014-04
影响因子：
9.2
通讯作者：
Jingbo Yan;Jingbo Yan;Hao Chen;Emir Dogdibegovic;J. Stevenson;Mojie Cheng;Xiao-Dong Zhou
中科院分区：
文献类型：
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作者：
Jingbo Yan;Jingbo Yan;Hao Chen;Emir Dogdibegovic;J. Stevenson;Mojie Cheng;Xiao-Dong Zhou
利用可逆固体氧化物电解池（SOEC）研究了中温区域二氧化碳的电化学还原。电流-电位（i-V）曲线在低电流密度下表现出非线性特性。 i-V 曲线的微分表明，电池面积比电阻 (ASR) 与电流相关，并且在电解模式下具有最大值，在燃料电池模式下具有最小值。在不同电流密度和气体成分下进行阻抗测量，并通过计算弛豫时间分布来分析结果。 ASR的变化是由于Ni-YSZ电极上发生的电化学反应的差异造成的，即Ni-YSZ对于CO氧化比对于CO2还原是更好的电极。 Ni-YSZ 上的焦炭形成对其在中温区的电解性能起着至关重要的作用。由于 CO2 还原反应的吸热性质，ASR 顶点与电解过程中电池温度的降低相关。据推测，温度的降低和 CO 浓度的升高导致了焦炭的形成。因此，建议采用更高的温度 (>700 °C)、更高的 CO2 浓度 (>50%) 以及氢气或蒸汽的存在，以在固体氧化物电化学电池中有效地减少 CO2。
Electrochemical reduction of carbon dioxide in the intermediate temperature region was investigated by utilizing a reversible solid oxide electrolysis cell (SOEC). The current–potential (i–V) curve exhibited a nonlinear characteristic at low current density. Differentiation ofi–Vcurves revealed that the cell area specific resistance (ASR) was current-dependent and had its maximum in electrolysis mode and minimum in fuel cell mode. Impedance measurements were performed under different current densities and gas compositions, and the results were analyzed by calculating the distribution of relaxation times. The ASR variation resulted from the difference in electrochemical reactions occurring on the Ni–YSZ electrode,i.e., Ni–YSZ is a better electrode for CO oxidation than for CO2reduction. Coke formation on Ni–YSZ played a crucial role in affecting its electrolysis performance in the intermediate temperature region. The ASR apex was associated with a decrease in cell temperature during electrolysis due to the endothermic nature of CO2reduction reaction. It was postulated that such a decrease in temperature and rise in CO concentration led to coke formation. As a consequence, higher temperature (>700 °C), higher CO2concentration (>50%), and the presence of hydrogen or steam are recommended for efficient CO2reduction in solid oxide electrochemical cells.