Properties of ZrO2:3 mol % Y2O3–(Na,K)2CO3–(Li,Na,K)2CO3 Triple-Layer Membranes for Carbon Dioxide Ion Permeation

ZrO2:3 mol % Y2O3 (3YSZ) ceramic powders were thoroughly mixed with poly­(methyl methacrylate) (PMMA), pressed into pellets, and subjected to heat treatment to prepare porous ceramics with high skeletal density by thermally removing PMMA. The porous 3YSZ pellets were first impregnated with a molten eutectic (Na,K)2CO3 (NKC) composition at 710 °C, followed by cooling to 420 °C for impregnation with a molten eutectic (Li,Na,K)2CO3 (LNKC) composition. The presence of sodium and potassium was evaluated by performing energy-dispersive X-ray analyses on the surfaces of triple-layer membranes. Permeation measurements were performed by using a homemade gas permeation setup. Electrical conductivity of carbon dioxide ions across the pellet thickness was measured at 475 °C for over 200 h by using impedance spectroscopy. No significant degradation of the electrical conductivity profile was observed during the test period, suggesting that the solid NKC layer acted as a protective barrier, preventing interaction between the 3YSZ ceramic and molten LNKC within the pore network.