Continuous Carbon Capture via Oxygen/Water Electrolysis in a Solid Electrolyte Reactor

Electrochemical carbon capture technologies, with renewable electricity as the energy input, are promising for carbon management but still suffer from low capture rates, oxygen sensitivity, or system complexity. Here we demonstrate a continuous electrochemical carbon capture design by coupling oxygen/water (O₂/H₂O) redox couple with a modular solid electrolyte reactor. By performing oxygen reduction (ORR) and oxygen evolution reaction (OER) redox electrolysis, our device can efficiently absorb dilute carbon dioxide (CO₂) molecules at the high-alkaline cathode/membrane interface to form carbonate ions, followed by a neutralization process through the proton flux from the anode to continuously output a high purity (> 99%) CO₂ stream from the middle solid electrolyte layer. No chemical inputs were needed, nor side products generated during the whole carbon absorption/release process. High carbon capture rates (440 mA cm^-2, 0.137 mmol_CO2 min^-1 cm^-2 or 86.7 kg_CO2 day^-1 m^-2), high Faradaic efficiencies (> 90% based on carbonate), high carbon removal efficiency (> 98%) in simulated flue gas, and low energy consumptions (starting from ~ 150 kJ/mol_CO2) were demonstrated in our carbon capture solid electrolyte reactor, suggesting its promising practical applications.