LAUSR

Abstract In this work, the plating of high‐quality amorphous nickel–phosphorous coating with low resistivity of 0.45 µΩ m (298 K) on complex 3D printed polymeric structures with high uniformity is reported. Such a polymer metallization results in an effective conductivity of 4.7 × 104 S m−1. This process also allows flexible structures to maintain their flexibility along with the conductivity. Octet‐truss structures with nickel–iron‐(oxo) hydroxide nanosheets electrodeposited onto further displays excellent water‐splitting performance as catalytic electrodes, i.e., in KOH (1 m, aq), a low oxygen evolution reaction (OER) overpotential of 197 mV at 10 mA cm−2 and Tafel slope of 51 mV dec−1. Using this light‐weight electrode with high specific area, strength, and corrosion resistance properties, a fully functional water‐splitting system is designed and fabricated through the concentric integration of 3D printed components. A dense polymeric mesh implemented is also demonstrated as an effective separator of hydrogen and oxygen bubbles in this system.