Solar-driven seawater desalination and electricity generation based on anisotropic graphene aerogel via unidirectional microfluidic transportation

Solar-driven interface evaporation for steam and electricity co-generation is expected to simultaneously solve the shortage of freshwater and energy. Although many different solar-driven evaporators have been developed, the simultaneously achieving freshwater-electricity cogeneration at a steadily high efficiency remains a challenge. In this work, an anisotropic graphene aerogel (AGA) with vertically aligned microfluidic channels is synthesized by a directional-freezing method. By unidirectionally transporting the saline, the AGA not only shows stable steam generation but also generates continuous electricity due to the formation of an asymmetric electric double-layer. For seawater desalination, the evaporation rate reaches about 2.82 kg m⁻² h⁻¹ under one sun irradiation. And the evaporation performance has no obvious attenuation after long-term usage due to self-operating salt rejection. During the seawater evaporation, the AGA can generate output voltage of ca. 0.85 V and short-circuit current of 0.01 mA. The AGA has the advantages of strong light absorption, high photothermal conversion ability, low thermal conductivity, low-cost, excellent salt rejection ability, making it very attractive for practical applications. Therefore, this work will provide a new opportunity for simultaneous solar desalination and electricity generation under natural sunlight.