LaxSr2-xFe1.5Ni0.1Mo0.4O6-δ对称电池电解CO2研究

固态氧化物电解池(SOECs)因较高的能量转化效率在电化学还原CO₂, 实现“碳中和”社会方面备受关注。与非对称电池结构相比, 对称SOECs的空气极和燃料极是相同或相近的材料, 可以减少界面种类, 改善电极与电解质的热膨胀匹配性, 简化电池的制备工艺。本研究合成了钙钛矿氧化物La_xSr_2-xFe_1.5Ni_0.1Mo_0.4O_6-δ (L_xSFNM, x=0.1、0.2、0.3、0.4), 作为固体氧化物电解池的对称电极用于评估纯CO₂的电化学还原性能。掺入La³⁺可以有效提高反应催化活性, 其中L_0.3SFNM为电极的电解池表现出最高的电化学性能, 800 ℃下, 在空气中的极化电阻为0.07 Ω?cm², 在50% CO-50% CO₂中的极化电阻为0.62 Ω?cm²。单电池L_0.3SFNM@LSGM|LSGM|L_0.3SFNM@LSGM在800 ℃和1.5 V电压下的电解电流密度为1.17 A?cm^-2, 在初始的50 h CO₂短期电解测试中表现出优异的稳定性, 是一种理想的对称电极材料。

Symmetrical La3+-doped Sr2Fe1.5Ni0.1Mo0.4O6-δ Electrode Solid Oxide Fuel Cells for Pure CO2 Electrolysis

Electrochemical reduction of the greenhouse gas CO₂ in solid oxide electrolysis cells (SOECs) has attracted much attention due to their high energy conversion efficiency and great potential for carbon cycling. Compared with the asymmetrical configuration, symmetrical SOECs with the same material as anode and cathode, can greatly simplify the fabrication process and reduce the complication associated with varied interfaces. Perovskite oxides La_xSr_2-xFe_1.5Ni_0.1Mo_0.4O_6-δ (L_xSFNM, x=0.1, 0.2, 0.3 and 0.4) are prepared and evaluated as symmetrical electrodes in solid oxide electrolysis cells for electrochemical reduction of pure CO₂. The polarization resistances are 0.07 Ω?cm² in air and 0.62 Ω?cm² in 50% CO-50% CO₂ for L_0.3SFNM electrode at 800 ℃. An electrolysis current density of 1.17 A?cm^-2 under 800 ℃ at 1.5 V is achieved for the symmetrical SOECs in pure CO₂. Furthermore, the symmetrical cell demonstrates excellent stability during the preliminary 50 h CO₂ electrolysis measurements.