Self‐Sustained Water and Electricity Generation from Ambient Humidity by Using Metal‐Ion Controlled Hygroscopic Hydrogels

Abstract Unlike traditional water production and electricity generation, direct utilization of atmospheric moisture is a promising way to simultaneously generate water and power. Here, a tailored hygroscopic hydrogel is developed through the coupling of electron empty orbitals and lone electron pairs, forming the [metal−N/O] moisture absorb active sites. The hydrogel aims to capture moisture from ambient humidity and transfer the gaseous water to liquid water, storing flowable water into the hydrogel. The moisture capture process includes two stages, initial a small amount of chemisorption on [metal−N/O] sites and followed by abundant physisorption on hydroxyls. Benefiting from the hygroscopic surface, the water uptake of Ni hydrogel is 0.92 g g ⁻¹ at 20 °C and 40% RH, while the dehydration temperature is only 40 °C. Packaging three layers of hydrogel, 4 mL h ⁻¹ drinking standard water is produced using only 9 g of hydrogel when exposed to ambient air and light. Upon creating a moist area by hydrogel and carbon paper as two electrodes, a stable open circuit voltage of 533.2 mV is generated in a self‐sustained manner.