Long-term electrochemical carbon capture from diverse CO2 sources with a recirculation mode.

Electrochemical carbon capture offers a sustainable pathway for carbon management, yet current systems are hindered by low concentration of atmospheric carbon dioxide (CO2), resulting in inefficiencies and limited stability. Here, we develop an electrochemical system employing a modular porous solid electrolyte (PSE) reactor for continuous, scalable carbon capture from diverse sources, including ambient air and flue gas, while regenerating high-purity CO2 ( >99%) without additional chemical input through a recirculation mode. By leveraging oxygen evolution and reduction reactions (OER/ORR) and employing sodium (bi)carbonate as a reversible cyclic mediator, the system achieves continuous CO2 capture from flue gas, delivering high Faradaic efficiencies for Na⁺ transport (~85%), and high carbon capture rates (3060 ml h-1 at 10 A, 100 cm2). Notably, direct air capture is demonstrated using ambient air, showing a long-term stability of over 2000 hours while maintaining high carbon removal efficiency (>93%) at 30 mA cm-2 and a large air treatment capacity (approximately 8820 kgair day-1 m-2), thus contributing to the goal of achieving net-zero emissions.