A Compact Hollow Fiber Electrode Assembly Architecture for Continuous Electrochemical Marine Carbon Dioxide Removal

ABSTRACT

While electrochemical direct ocean capture (e‐DOC) offers a plausible pathway for gigaton‐scale decarbonization, its practical deployment remains bottlenecked by complex reactor architectures, constrained fluid‐electrode interfacial areas, massive Ohmic penalties, and severe mineral fouling. Herein, a compact, membrane‐integrated hollow fiber electrode assembly architecture that systematically overcomes these limitations for continuous marine carbon mineralization is reported. Macroporous stainless‐steel hollow fibers, fabricated via scalable fiber spinning and sintering, deliver an expansive electrochemically active surface area alongside exceptional mechanical robustness and corrosion resistance. Crucially, by seamlessly integrating a membrane and a counter electrode within the fiber lumen, a sub‐millimeter inter‐electrode spacing (≈1 mm) is established. This coaxial configuration reduces ionic transport pathways and minimizes Ohmic losses, driving localized hydroxide generation with effective pH swing for rapid dissolved inorganic carbon (DIC) removal. Furthermore, the membrane‐integrated working electrode design effectively mitigates fouling, enabling stable continuous operation for over 100 h while delivering a DIC removal efficiency exceeding 85%. This advanced materials‐to‐device platform establishes a robust, high‐throughput paradigm for practical ocean decarbonization.