High-performance moist-electric generator based on dynamic network design of functionalized nanocellulose hydrogel.

Hydrogels are characterized by their exceptional hydrophilic properties, rendering them optimal active materials for moist-electric generator (MEG). Nonetheless, insufficient protonation and ionic diffusion compromise the electrical properties of hydrogels, thereby limiting their practical applications. In this study, an ionic conductive hydrogel based on the combination of functionalized nanocellulose (FCNF) and polyacrylamide (PAM) was developed by UV-initiated polymerization and solvent substitution. The FCH hydrogel has good stretchability (250 %) and high conductivity (17.3S m^-1). In addition, the MEG was constructed using FCH hydrogel. The MEG device has excellent electrical output performance, with open circuit voltage, short circuit current density and maximum power density of 1 V, 1.38 μA cm^-2 and 63 nW cm^-2, respectively. At the same time, the MEG also has stable environmental adaptability, and can maintain stable output in a wide humidity range (15-98 %RH) and low temperature (-20 °C). Notably, MEG exhibits scalability through series/parallel configuration, achieving current and voltage outputs of 4.0 V (five series units) and 5.4 μA (five parallel units), and can also be directly used as a power supply to power capacitors and LED light. This work presents a novel approach for developing simple, environmentally friendly, and efficient MEGs for portable self-powered flexible devices.