Transparent, Self-Adhesive, Conductive Organohydrogels with Fast Gelation from Lignin-Based Self-Catalytic System for Extreme Environment-Resistant Triboelectric Nanogenerators

Conductive hydrogels have shown great promise in the field of sustainable power sources due to their unique features of sufficient flexibility, durability, and functional diversification. However, time- and energy-consuming polymerization process and poor adaptability in extreme environments severely impede their practical application in such an emerging field. Herein, a facile and universal self-catalytic system (AL-Cu2+) based on alkali lignin (AL) macromolecule has been designed to rapidly fabricate conductive and transparent organohydrogels in alkaline water-ethylene glycol (EG) binary solvent, which displays extreme environment applicability (-40 to 60 degrees C), eligible stretchability (approximate to 800% elongation), and robust self-adhesion (approximate to 31.4 kPa). Interestingly, the introduced EG accelerates the polymerization, endows extreme freezing/drying resistance, and improves self-adhesion for the organohydrogels. The organohydrogel (water/EG = 2/3) that combines the above merits inspires the construction of triboelectric nanogenerator (O-TENG) for mechanical energy harvesting and converting regardless of low- or high-temperature environments. The generated electricity by the O-TENG can be used directly or stored to drive commercial electronics and installed on human joints for movement monitoring. This work sheds light on designing environment-resistant flexible TENGs based on multifunctional soft materials with fast gelation strategy, provoking more attention to sustainable high-value utilization of lignin for advanced applications.

Automated summary

This study designs a facile and universal self-catalytic system based on alkali lignin to fabricate conductive and transparent organohydrogels. The organohydrogels exhibit extreme environment applicability, eligible stretchability, and robust self-adhesion. They can be used to construct triboelectric nanogenerators for mechanical energy harvesting and converting, as well as for applications in commercial electronics and human movement monitoring.