Scale‐Expandable All‐Wood‐Based Hydrogel for Highly Efficient Desalination Enabled by 3D Printing and Array Design

Fully utilizing all components of waste biomass while enabling scalable structural design remains a critical challenge for solar‐driven interfacial desalination. Herein, we convert waste wood powder into an all‐component wood based (all‐wood‐based) hydrogel (AWH) solar evaporator via one‐step reusable ionic compounds (ICs) composed of ZnCl 2 and CaCl 2 , and through 3D printing and array design, a scale‐expandable pyramid‐structure array evaporator for efficient desalination was realized. Unlike common methods that need specified component extraction or removal, this IC strategy simultaneously dissolves and regenerates the three primary wood components (cellulose, hemicellulose, and lignin). The AWH achieves a remarkable solar evaporation rate of 2.94 kg m − 2 h − 1 and a good solar energy‐to‐vapor efficiency of 96.81%, enabling stable long‐term desalination without salt accumulation. Even after 96 h evaporation, it can still maintain an evaporation rate of 2.53 kg m − 2 h − 1 . Furthermore, a pyramid‐shaped AWH evaporator obtained by 3D printing demonstrates a high evaporation rate of 3.45 kg m − 2 h − 1 , and its 3×3 pyramid‐shaped array achieves a remarkable evaporation rate of 3.33 kg m − 2 h − 1 even by creating a T‐shaped high‐speed steam flow channel above the array. This eco‐friendly and scalable wood‐based hydrogel offers a viable approach to addressing global water scarcity.