Periodic Porous 3D Electrodes Mitigate Gas Bubble Traffic during Alkaline Water Electrolysis at High Current Densities

Alkaline water electrolysis at high current densities is plagued by gas bubble generation and trapping in stochastic porous electrodes (e.g., Ni foams), which causes a significant reduction in the number of electrolyte accessible catalyst active sites. Here, 3D printed Ni (3DPNi) electrodes with highly controlled, periodic structures are reported that suppress gas bubble coalescence, jamming, and trapping and, hence, result in rapid bubble release. The 3DPNi electrodes decorated with carbon‐doped NiO achieve a high current density of 1000 mA cm−2 in 1.0 m KOH electrolyte at hydrogen evolution reaction and oxygen evolution reaction overpotentials of 245 and 425 mV, respectively. This work demonstrates a new approach to the deterministic design of 3D electrodes to facilitate rapid bubble transport and release to enhance the total electrode catalytic activity at commercially relevant current densities. This work demonstrates a new approach to the deterministic design of 3D electrodes to minimize the deleterious effects of gas bubbles by carefully engineering porous highways and transport networks that facilitate rapid bubble transport and release to enhance the total electrode catalytic activity at commercially relevant current densities.