Orchestrated Multiscale Effects Boost Performances of Hybrid Carbon-Based Water-Electricity Cogenerators

The performance of solar-powered evaporating materials is significantly influenced by their multiscale structures, which exhibit both synergistic and antagonistic effects that are complex and challenging to be harnessed. Here in this study, using a carbon nanotube sponge of optimized thickness, pore sizes, and oxidized silicon coating layers, we proposed a facile and robust design of a water-electricity cogenerator, indicating that orchestrated multiscale effects (macro, meso, micro) can synergistically boost the performances of evaporation. Specifically, we highlighted the importance of mesoscale capillary water, which is often neglected, indicating not only the promotion of water transportation but also the expansion of sufficient evaporative surface area. The cogenerator, named as SiO_x@CNTS, exhibited light absorption of up to 96%, a water evaporation rate of 7.01 kg m^-2 h^-1 under 1 sun, 21.75 kg m^-2 h^-1 under 10 suns, 16.62 kg m^-2 h^-1 in dark conditions with a wind speed of 3 m s^-1, a continuous output voltage of up to 1.02 V under 1 sun during water desalination, excellent salt resistance, and cycling stability with no salt aggregation on the upper surface. Our study offers insights into the design of next-generation evaporators that utilize solar energy for sustainable and high-efficiency water-electricity cogeneration.