Breaking the strength-activity tradeoff in high-temperature CO2 electrolysis with a hybrid solid oxide cell

Electrochemical conversion of CO2 into chemicals and fuels offers a promising route towards a circular carbon economy. High-temperature CO2 electroreduction in solid oxide electrolysis cells (SOECs) delivers high selectivity and energy efficiency, but suffers from a tradeoff between mechanical robustness and electrochemical activity. Here we resolve this constraint using a hybrid ionic-conductor architecture that decouples electrocatalysis, ionic transport and mechanical support into function-specific layers. The resulting cell achieves one of the highest reported mechanical strengths (fracture load >7 N), while delivering 1.5-3.0fold higher CO2-to-CO activity than state-of-the-art SOECs over operating temperatures of 600-800 °C. Stable operation is maintained for over 1,000 hours at a current density of 1.0 A cm-2. Furthermore, we demonstrate scalability with a single-cell area of 100 cm 2 , achieving total currents up to 120 A and powers up to 200 W. This work establishes a general strategy for developing mechanically resilient, efficient, and scalable energy conversion devices. Posted on 25 March 2026-CC-BY 4.0-This is a preprint and has not been peer reviewed. Data may be preliminary.