Phase Change Material Boosting Electricity Output and Freshwater Production through Hierarchical‐Structured 3D Solar Evaporator

Abstract Intermittent sunlight irradiation severely limits the performance of solar evaporators for electricity output and freshwater production. To address this issue, a hierarchical‐structured three‐dimentional (3D) solar evaporator to simultaneously enhance output voltage and freshwater production by integrating a paraffin‐type phase change material (PCM) with a circular concave‐shaped 3D supporter covered with a carbon‐black‐nanoparticles‐modified poly(ethylene terephthalate) fabric (PMCB) is developed. In this developed 3D solar evaporator, the 3D‐printed supporter can trap sunlight to improve solar energy absorption, and the PMCB obtained from hydrophilic and hydrophobic modification can adequately absorb sunlight for electricity generation and water evaporation, resulting in a maximum output voltage of 3.51 V and a high evaporation rate of 4.0 kg m −2 h −1 under natural sunlight illumination. Owing to the introduction of the PCM, the 3D solar evaporator obtains a decrease in the time required for charging a capacitor by 57.9% and an increase in freshwater production by 29.9% compared to the counterpart without a PCM. Through rationally utilizing the solar photothermal energy stored by the PCM and innovatively integrating the PCM and PMCB in a hierarchical‐structured 3D supporter, the developed 3D solar evaporator exhibits great application potential for simultaneous electricity generation and freshwater supply under intermittent solar irradiation.