Integrating a Phase-Change Core and a Photothermal Fabric Shell for High-Efficiency Solar Desalination and Water Treatment

Water stress presents a critical threat to the advancement of global sustainable development. With the advantages of low-carbon operation and high efficiency, solar-driven interfacial evaporation has emerged as a highly promising technology. However, the inherent intermittency of solar energy severely limits its continuous operation and practical application. To achieve this goal, this work proposes an innovative design strategy of matrix stabilization-functional encapsulation, constructing a functionally integrated "energy storage core-evaporation shell" core-shell structure evaporator. This evaporator employs an inner composite phase-change aerogel as its thermal management core, enabling controlled heat storage and release. The outer layer utilizes polypyrrole (PPy)-modified hydrophilic nonwoven fabric to simultaneously achieve favorable photothermal conversion and rapid directional water transfer. Consequently, the thermal management pathway and water transport pathway are synergistically optimized, effectively resolving issues such as insufficient coupling between thermal and water pathways. Experiments demonstrate that this evaporator achieves 97% solar absorption efficiency, with an evaporation rate of 2.22 kg m-2 h-1 and a photothermal conversion efficiency of 96.04%. Even after illumination ceases, the system can sustain evaporation at a rate of 0.92 kg m-2 h-1 for 1 h, a process driven by latent heat released from phase-change materials. This enables the evaporation process to extend from illuminated periods to nonilluminated periods. Furthermore, the evaporator demonstrates outstanding stability and purification performance in various complex water environments. Through synergistic structural and material design, this work achieves efficient integration of energy storage units with an evaporation interface.