Naturally O-N-S Co-Doped Carbon with Multiscale Pore Architecture Derived from Lotus Leaf Stem for High-Performance Supercapacitors

Lotus leaf stem is successfully exploited as a sustainable biomass to fabricate multi-heteroatom co-doped carbon with multiscale pore architecture by a readily scalable and effective strategy of pre-carbonization and KOH activation. By taking advantage of 3D hierarchical structure with high surface area and optimized pore size distribution, naturally O-N-S co-doping and nanosized graphitic structure (contributing to large accessible surface for charge storage, short ion diffusion distance, rapid charge transfer and low internal resistance), as-produced carbon is demonstrated as a promising electrode for supercapacitors with a high capacitance of 425 F/g at 0.5 A/g in a three-electrode system and 295 F/g at 0.1 A/g with superb rate capability (84% retention from 0.2 to 20 A/g) and outstanding recyclability (97.8% retention after 10000 charge-discharge cycles at 10 A/g) in a two-electrode system with KOH solution. The excellent recyclability of 93.3% is also achieved after 10000 cycles at 10 A/g for the symmetric supercapacitor using Na2SO4 electrolyte. These values may boost the commercial application of biomass-derived carbon for energy storage.

Automated summary

Utilizing lotus leaf stem as raw material, carbon materials fabricated with multiple advantages including high surface area, optimized pore size distribution, 3D hierarchical structure, nanosized graphitic structure, and natural heteroatom co-doping exhibit excellent performance in supercapacitors, showing high capacitance, superior rate capability, and outstanding recyclability.