Advances in porous carbons from biomass-derived macromolecules for supercapacitors

Carbonaceous frameworks dominate supercapacitor electrodes owing to reversible electrostatic charge storage, exceptional cycling stability, and broad structural tunability. The structural diversity of porous carbons benefits from an expanding spectrum of precursors and synthetic methodologies. Among these, biomass-derived macromolecules, including lignin, polysaccharides, and proteins derived from terrestrial plants, algae, microbes, and animal biomass, stand out for renewability, abundance, and inherent structural heterogeneity, offering a sustainable platform for tailored carbons. These biopolymeric feedstocks exhibit diverse chemical functionalities and reactivities that endow exceptional design flexibility for modulating carbon surface chemistry, hierarchical pore architectures, and heteroatom doping. This review appraises advances in the preparation, structural engineering, and capacitive deployment of porous carbons from biomass-derived macromolecules. It systematically elaborates trajectories for constructing multimodal pore networks, micropores for charge storage, mesopores as ion-transport highways, and macropores as electrolyte reservoirs, via chemical activation, sacrificial templating, and emerging molten-salt strategies. Complementary paradigms for endogenous and exogenous heteroatom incorporation are discussed, which synergistically modulate electronic structures, enhance interfacial wettability, and inject pseudo-capacitance. Moving beyond isolated precursor-specific reports, this review advances a precursor-taxonomy-guided framework that unifies lignin-, polysaccharide-, and protein-derived systems through shared structure–property–performance principles, thereby streamlining the selection of biomass-derived macromolecule feedstocks, synthetic protocols, and device configurations for sustainable supercapacitor electrodes.