In a solid-liquid dual-phase CO₂ separation membrane, the native ions in the molten alkali carbonate, including carbonate anions and metal cations can transport CO₂ in a process that is charge-compensated by electronic species (electrons or holes), oxide ions, or hydroxide ions, depending on materials and conditions. This strongly affects the design of experiments for assessing the performance of these membranes, and further determines the routes for integration of these membranes in industrial applications. Here we report how dissolved oxides in the liquid carbonate improve the CO₂ flux of the membrane due to an enhanced charge-compensating oxygen ion transport. A qualitative understanding of the magnitude and role of oxide ion conductivity in the molten phase and in the solid support as a function of the temperature is provided. Employing a solid matrix of ceria, and dissolving CsVO₃ and MoO₃ oxides in the molten carbonate phase led to an almost doubled CO₂ flux at 550 °C under dry ambient conditions. When the sweep gas contained 2.5% H₂O, the CO₂ flux was increased further due to formation of hydroxide ions in the molten carbonate acting as charge compensating species. Also, as a consequence of permeation controlled by ions in the liquid phase, the CO₂ flux increased with the pore volume of the solid matrix.

在固液两相CO ₂分离膜中，熔融的碱金属碳酸盐中的天然离子（包括碳酸盐阴离子和金属阳离子）可以在通过电子物质（电子或空穴），氧化物进行电荷补偿的过程中传输CO ₂。离子或氢氧根离子，具体取决于材料和条件。这极大地影响了评估这些膜性能的实验设计，并进一步确定了在工业应用中将这些膜整合在一起的途径。在这里，我们报告液态碳酸盐中的溶解氧化物如何改善CO ₂由于增强的电荷补偿性氧离子传输，导致膜通量增加。提供了对熔融相和固体载体中氧化物离子电导率的大小和作用随温度变化的定性理解。使用二氧化铈的固体基质，并将CsVO ₃和MoO ₃氧化物溶解在熔融的碳酸盐相中，导致在550°C的干燥环境条件下，CO ₂通量几乎翻倍。当吹扫气体包含2.5％的H ₂ O时，由于在充当电荷补偿物质的熔融碳酸盐中形成氢氧根离子，所以CO ₂通量进一步增加。而且，由于液相中离子控制的渗透作用，CO ₂ 通量随固体基质的孔体积而增加。