Cu 2-x S@CaCl 2 -Based Fabric with a Tunable 3D Structure for Continuous Solar-Driven Freshwater Generation and Electricity Supply in Harsh Environments

Solar-driven evaporation is considered as a sustainable technology to solve the global challenge of freshwater scarcity and uneven electricity development. However, maintaining a high freshwater yield and excessive power output by reusable and economical solar evaporators remains a challenge in arid regions and islands. Herein, a portable and scalable solar evaporator is elaborately devised for highly efficient simultaneous freshwater and power generation. In the integrated solar evaporators, Cu_2-xS-based fabric acts as an outstanding water generator though superior photothermal conversion of Cu_2-xS and high hygroscopicity of CaCl₂. And the temperature gradient derived from rapid interfacial evaporation is applied for electricity generation. In addition, inspired by Hedgehogs, the solar evaporator with a unique three-dimensional structure enables multiple optical absorption and directional water supply, which was proposed to promote moisture harvesting, water evaporation, and hinder salt crystallization. The evaporator without utilization is also folded to reduce the space occupation. The Cu_2-xS-based solar evaporator efficiently harvests water from the atmosphere with an excellent moisture adsorption capacity (0.46-0.90 g g^-1) at a wide range of relative humidity (40%-80%). Noteworthily, the Cu_2-xS-based solar evaporator not only achieves an outstanding evaporation rate at different incident angles and intensities but also utilizes wind for evaporation. And an impressive 220.09 mV output voltage was obtained by the evaporator equipped with a thermoelectric module. The solar evaporator endures a high water yield of 27.44 kg m^-2 per day and a maximum output voltage of 190.67 mV under natural irradiation. This study introduces a groundbreaking Cu_2-xS-based solar evaporator equilibrating excellent effectiveness and practicality, which provides new avenues for freshwater harvesting and an electricity supply in harsh environments.