Highly efficient atmospheric water harvesting via a biomimetic condensation structure integrated with passive radiative cooling

Abstract Atmospheric water harvesting (AWH) via thermoelectric condensation offers a promising solution for localized water scarcity but is constrained by high energy consumption and low energy efficiency. In this study, we employ selective laser melting (SLM) technology to fabricate a biomimetic 3-D condensation structure. The synergistic effects of geometric curvature gradients and optimized surface wettability significantly enhance water collection efficiency compared to conventional fin designs. Electrochemical polishing is further applied to reduce surface pinning effects, thereby promoting droplet removal. Additionally, a superhydrophobic passive radiative cooling coating is introduced onto the structure’s surface. This coating reflects a substantial portion of incident solar radiation and continuously emits thermal radiation through the atmospheric window, effectively reducing cooling energy demand. Under an applied power of only 56.3 mW cm − 2 , the biomimetic structure achieves a water collection rate of 247.54 mg cm − 2 h − 1 , which is 4.7 times higher than that of a commercial fin condenser. Field testing demonstrates that incorporating the passive radiative cooling coating improves water harvesting efficiency by up to 39.8%. This study presents a viable approach to enhancing the performance of thermoelectric AWH systems, laying a foundation for mitigating the global water-energy conflict.