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

Polymers obtained from biomass are promising alternatives to petro-based 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 lignin-based 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.