Self-optimized and stable nanocomposites via one-pot synthesis for high-temperature CO2 electrolysis in solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) hold the promise of directly converting CO2 into CO fuels with exceptional cost-effectiveness and efficiency. However, the widespread application of SOECs is impeded by the significant lack of highly active and stable cathodes. Herein, a one-pot synthesis strategy is proposed to introduce Cu into a composite consisted of Sr2Fe1.5Mo0.5O6−δ (SFM) and Gd0.2Ce0.8O1.9 (GDC). This strategy leads to the automatic formation of hetero-structured composites, comprising double perovskite, Ruddlesden-Popper perovskite, fluorite, as well as in-situ exsolved Cu–Fe bimetals at high temperatures and operational conditions. Consequently, this approach greatly enhances CO2 adsorption capability, CO2 catalytic activity, O2−/e− conductivity, and ensures good phase compatibility with electrolyte. As results, the La0.8Sr0.2Ga0.8Mg0.2O3−δ electrolyte-supported single cell with the composite cathode achieves a high current density of 2.22 A cm−2 at 850 °C and 1.6 V, which is substantial increase of 65.7% compared to the current density achieved with traditional physically hybrid SFM-GDC cathodes. These results underscore the potential of one-pot synthesized nanocomposites as promising cathodes for CO2 electrolysis in SOECs.