Carbon Nanotube Network-Based Solar-Thermal Water Evaporator and Thermoelectric Module for Electricity Generation

A combination of an interfacial solar-thermal water evaporation device and a power module has been emerging to alleviate the shortage of fresh water and electricity. Nevertheless, the effective integration of a solar evaporator and a power module to achieve both high water evaporation and power generation remains a significant challenge. Herein, the ultrafast interfacial solar-thermal water evaporation and good power generation have been realized through the effective integration of a carbon nanotube (CNT) network-based evaporator and a thermoelectric (TE) module. In the device, the hydrophobic CNT film as a heater surrounding all around, coupled with hydrophilic CNT foam/poly­(vinyl alcohol) (PVA) as an evaporator located in the core region, forms an evaporative layer, which is followed by the TE module and a paraffin layer below that acts as the power-generating layer. Under solar irradiation, the temperature gradient between the hyperthermal CNT film and the paraffin layer is formed, which enables the TE module in between to generate electricity. Meanwhile, the ceramic material on the TE module surface can rapidly transfer the heat from the edge of the heating layer (CNT film) to the central evaporation layer (CNT foam/PVA), thus significantly improving the heat utilization from the heating layer. Consequently, the output power density can reach 0.4 W m–2 with an ultrafast water evaporation rate of 5.0 kg m–2 h–1 under 1 sun irradiation. This integrated solar energy device provides potential opportunities for fresh water and electricity supply in off-grid or remote areas.