Polyphenolic Mechanochemistry-Mediated Liquid Metal Hydrogels for Efficient Solar-Powered Desalination and Electricity Generation

Abstract

Solar-powered desalination and electricity generation have attracted great interest owing to their great potential to mitigate the worldwide freshwater shortage and energy crisis. Liquid metal (LM), as a class of conductive photothermal materials, is highly anticipated in this field due to its unique surface plasmon resonance effect and highly delocalized free electron properties. Nevertheless, its practical application is still limited by the narrow light absorption range and poor dispersibility. In response to those critical challenges, this study proposes a polyphenolic mechanochemistry-mediated interfacial engineering strategy, which utilizes the powerful shear force and abundant chemical interactions of polyphenols to improve the interfacial properties and photothermal performance of LM. The resultant polyphenol-coated LMs are further incorporated into functional hydrogels to impart superior photothermal performances and interfacial compatibility. Consequently, a high evaporation rate of 3.60 kg m−2 h−1 is achieved under 1 sun illumination, exceeding all LM-based evaporators to the best of current knowledge. Moreover, the unique electrical features of LM offer excellent performance for efficient water evaporation-induced electricity generation, with a stable electrical output of 250 mV, 0.257 mA under 1 solar illumination. This work provides a novel surface engineering strategy for LMs using natural molecules, showcasing their potential for environment and energy realms.