From double-helix structured seaweed to S-doped carbon aerogel with ultra-high surface area for energy storage

：A sustainable biomass conversion and green strategy, using red algae derived carrageenan-Fe hydrogel as precursor, is developed to fabricate the 3D hierarchical macro-meso-microporous sulfur-doped carbon aerogel (HPSCA) with tunable nanopores and ultra-high surface area up to 4037.0 m2 g−1. The molecular-level dispersions of Fe3+ ions in carrageenan contribute to the ultra-high surface area of HPSCA after carbonization, acid washing and...