Continuous carbon capture in an electrochemical 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 1-6 . Here we demonstrate a continuous electrochemical carbon-capture design by coupling oxygen/water (O 2 /H 2 O) redox couple with a modular solid-electrolyte reactor 7 . By performing oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) redox electrolysis, our device can efficiently absorb dilute carbon dioxide (CO 2 ) 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%) CO 2 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 consumption (starting from about 150 kJ per mol CO2 ) were demonstrated in our carbon-capture solid-electrolyte reactor, suggesting promising practical applications.