Advances Toward Sustainable Lignin-based Gel for Energy Storage and Smart Sensing

Polymers obtained from biomass are promising alternatives to petrobased polymers owing to their low cost, biocompatibility, and biodegradability.Lignin, a complex aromatic polymer containing several functional hydrophilic and active groups including hydroxyls, carbonyls, and methoxyls, is the second most abundant biopolymer in plants.In particular, sustainable ligninbased gels are emerging as an appealing material platform for developing energy-and sensing-related applications owing to their attractive and tailorable physiochemical properties.This study describes the preparation strategies of lignin-based gels according to previously reported methods, with significant attention on the diverse performance of lignin-derived gel materials.Additionally, a detailed review of lignin-based gels utilized as an important resource in diverse fields is provided.Finally, a future vision on challenges and their possible solutions is presented.