Flexible wood-based composite for solar water evaporation and waste heat power generation

Abstract

Solar water evaporation shows great promise in the utilization of sunlight resources. However, currently available evaporators suffer from poor mechanical properties, easy leakage and failure of heat conversion materials, and single utilization pattern limit the equipment can not be widely used. In this study, a wood composite with good flexibility, efficient photothermal conversion was prepared using delignified wood (DW), polymerizable deep eutectic solvent (PDES) and Ti3C2Tx (MXene) nanosheets. DW was a hydrophilic substrate to provide water transport channels. The MXene nanosheets were uniformly dispersed in the DW matrix through hydrogen bonding for efficient light absorption and photothermal conversion, while PDES provided flexibility to the material, allowing it to be shaped as desired. Meanwhile, the addition of PDES not only effectively prevents the oxidation of MXene nanosheets, but also helps MXene to be encapsulated in the composite material and provides some flame retardant effect. In addition, through the combined use of semiconductor thermoelectric power modules (SP modules), waste heat can be directly used for power generation. Under 1 solar irradiation, the water evaporation rate could reach 1.59 Kg/m2/h, the power density of photothermal power generation was 0.71 W m−2, and the photothermal conversion efficiency is 95.24%. The device can operate for a long time in extreme environments, providing fresh water and electricity to resource-constrained areas.