Electrochemical direct air capture (EC-DAC) system using sodium fuel cell

Herein, we develop electrochemical direct air capture (EC-DAC) system using molten Na fuel cell. The electrochemical reaction consists of Na oxidation and O 2 /CO 2 reduction at the anode and cathode, respectively, and the coupled reaction generates the electricity and Na 2 CO 3 . The coin cell maintains DAC performance for 400 s at a current of 4 mA with air flow (600 sccm) and heating (150 ℃). We also demonstrate a pilot cell where the active area is 50 times larger than the coin cell. It displays a carbon capture efficiency of 37.2 % for 6600 s under an air flow of 7000 sccm by detecting a concentration of CO 2 from inlet and outlet using GC. • An electrochemical direct air capture (EC-DAC) system utilizing a molten Na fuel cell was developed, demonstrating simultaneous CO 2 capture and electricity generation. • The system maintained stable direct air capture performance for 400 s at 4 mA with an air flow of 600 sccm and heating at 150 ℃ using a coin cell. • A scaled-up pilot cell, 50 times larger than the coin cell, achieved a carbon capture efficiency of 37.2 % for 6600 s under an air flow of 7000 sccm. • The use of carbon nanotubes (CNT) coated on both the carbon cloth cathode and the NASICON separator significantly improved electrochemical performance and CO 2 capture efficiency by preventing blockage from formed Na 2 CO 3 .