Highly Compact Nano-Channelled Thin Films with Exceptional Thermal Conductivity and Water Pumping

Synergetically integrating multiple capabilities into a nanostructured material has becoming one kind of reliable and sustainable strategies for resolving the tricky issues in energy and environmental fields. Herein, we prepare a series of nano-channelled thin films by simply assembling of cellulose nanofibers with reduced oxide graphene, dominantly driven through van der Waals interactions. The thicknesses of the as-prepared thin films can be well controlled within several micrometers. Their highly compact nano-channelled structures were manifested by the densities of up to 1.1 g cm-3 and the largest Brunauer-Emmett-Teller specific area of 126 m2 g-1, endowing them with the excellent hygroscopicities (282 mg g-1), and the exceptional in-plane thermal conductivities (614~1238 W m-1 K-1 with respect to 25~80 oC), among the highest values for the carbon-based composites. Such thin-film composites are readily manipulated into solar-steam generators, delivering a record volumetric evaporation rate of 122 kg L-1 h-1 with an efficiency of ~95%, which are also facile to be integrated into an high-performance amplified system for the desalination in large scale under natural solar irradiation.