Biomimetic Structural Design of Fabric for Low‐Cost, Scalable, and Highly Efficient Off‐Grid Solar‐Driven Water Purification

Abstract Interfacial solar‐vapor generation (ISVG) is an emerging technology for water purification. However, high cost, low evaporation rate, clogging issues, and limited solar utilization under natural condictions greatly hinder its practical application. Herein, inspired by the aligned microstructure of dragonfly wings, a 3D microarray structure composed of vertically aligned hierarchical and hydrophilic carbon fibers (CFs) is constructed using a scalable fiber manufacturing technology. The microarray structure of the high‐thermal‐conductivity CFs with nanocapillaries contributes to the fast mass (steam and salt ions) and heat transfer as well as high omnidirectional light absorption. More importantly, due to the strong multiscale capillary effect, the formed 3D water evaporation surface containing abundant micro‐meniscuses and nanoscale thin water layers in the CFs arrays effectively reduces the evaporation enthalpy and creates more water/air interfaces, leading to the significant increasing evaporation rate. As a result, a high evaporation rate of 2.21 kg m⁻² h⁻¹ under one‐sun irradiation can be achieved. Moreover, the off‐grid water treatment device assembled with multiple 3D CFs‐based customized spherical evaporators can obtain a high pure water collection of 10.71 kg m⁻² per day without salt accumulation under real environmental conditions. This work demonstrates a high‐efficiency, cost‐effective, and scalable strategy for high‐performance ISVG.