Easy hydrogel preparation with high-purity lignin separated from DES pretreatment with excellent performance for moisture-electric generators and motion sensors

Abstract

This study presents a rapid and straightforward method to prepare a multifunctional hydrogel using deep eutectic solvent-pretreated lignin (DESL), aluminum ions (Al³⁺), and polyacrylic acid (PAA) in an aqueous system. With its high purity, DESL proves to be an exceptional raw material for producing hydrogel-based moisture-induced electricity generators (HMEGs), outperforming alkali lignin in availability and lignosulfonates in versatility. The resulting hydrogel exhibits remarkable self-adhesive, flexible, plastic, and self-healing properties with a tensile strength of 1.57 MPa and elongation at break of 1580%. A single 1 cm × 1 cm × 0.3 cm HMEG generated an impressive open-circuit voltage of 1.32 V and short-circuit current of 22.37 μA, demonstrating its ability to function as a self-powered motion sensor. This study puts forward a novel approach to maximize the value of DESL and expedite the development of a cost-effective and efficient hydrogel-based moisture energy harvester with ecological considerations.