Breaking the transport limit of the rib-channel flow field to enable amp-level CO2 electrolysis and high-purity CO output

Industrial implementation of electrochemical CO 2 reduction requires maximizing both throughput and durability. While conventional rib-channel flow fields are the current standard, further elevating their performance is constrained by the inherent trade-offs involving CO 2 transport, water management, and salt precipitation behavior. To overcome these coupled challenges, we introduce a 3D foam flow field architecture. This design utilizes an interconnected porous structure to provide moderate convective transport, effectively mitigating local CO 2 starvation and enabling effective passive water management. Consequently, we achieve a CO Faradaic efficiency of 90% at an industrially relevant current density of 1,000 mA cm −2 . The optimized transport yields a high CO product concentration of 74 vol % and increases single-pass conversion to 43%. The device also demonstrates superior stability with a degradation rate only 1/14 of the baseline design, maintaining performance for over 400 h. This highlights that advanced flow field engineering is essential for unlocking industrial-scale CO 2 electrolysis.