Sustainable Lignin-Based Ionic Hydrogel for High-Performance Moisture-Electric Generation and Self-Powered Wearable Sensing

Abstract

The development of sustainable and high-performance hydrogel-based moisture-induced electric generators (HMEGs) is crucial for advancing self-powered electronics but remains challenging due to tedious fabrication processes, low output current, and the use of toxic reagents. The resulting EHL-Al³⁺-poly (acrylic acid) (PAA) hydrogel achieves rapid gelation within approximately 1 minute at ambient temperature, with the entire preparation process completed in 10 minutes. This hydrogel exhibits remarkable multifunctionality, serving simultaneously as a robust strain sensor and a high-performance MEG. It features rapid self-healing (<1 min), superior mechanical properties (over 500% stretchability), and high ionic conductivity (5.15 S/m). As a strain sensor, it achieves a high gauge factor of 15.2 for real-time monitoring of human motions. When configured as an asymmetric moisture-electric generator (Zn//Carbon cloth), the device delivers a high electrical output of 1.71 V and 2.5 mA. Practical applicability is demonstrated by powering commercial light-emitting diodes (LEDs) for over 240 hours and driving electronic sensors using only two series-connected units. This work establishes a new paradigm for eco-friendly, high-output, and self-sustaining power sources, paving the way for next-generation wearable electronics and Internet of Things (IoT) systems.