Biobased Bionic Spider Silk via Electrostatic Complexation for Simultaneously Harvesting Atmospheric Water and Triboelectric Energy

Abstract Atmospheric water harvesting has emerged as a sustainable solution for overcoming water and energy shortages. Herein, an entirely biobased bionic spider silk (chitosan–sodium alginate filament [CSF]) is prepared using an interfacial, aqueous, and straightforward polyelectrolyte complexation with a continuous drawing technique, simultaneously harvesting water and triboelectric energy from ambient humidity. CSF exhibits a periodic spindle‐shaped structure resembling spider silk, with surface roughness conducive to atmospheric water harvesting. The success of the electrostatic complexation technique for CSF is confirmed by water solubility, Fourier‐transform infrared spectroscopy, and thermogravimetric analyses. The production yield of CSF reaches the maximum of 99.36% by controlling the substrate type and polyelectrolyte mass ratio. Moreover, fog‐harvesting efficiency peaks at 1552.83 mg cm −1 h −1 (1.0 wt.% polyelectrolyte concentration), demonstrating concentration‐dependent performance. Subsequently, CSF is woven into a bionic spider web (CSW) for simultaneous water and energy harvesting. Through parametric optimization, the CSW‐based droplet triboelectric nanogenerator system achieves 180 V and 72.25 µW output. When deployed in a high‐humidity greenhouse, the system powers 80 light‐emitting diodes, a hygrometer (thermometer), and a stopwatch. This study presents a straightforward, effective, and green strategy for simultaneously harvesting water and energy from the ambient environment, providing fresh water and renewable energy to enhance sustainability.