Biomass -Derived Activated Carbon Nanostructure for Sustainable Supercapacitors

Abstract

The escalating global demand for energy storage solutions, coupled with the pressing need for environmental sustainability, has driven intensive research into green, high-performance supercapacitor electrode materials. This review systematically examines the synthesis, characterization, and electrochemical performance of activated carbon nanostructures derived from diverse biomass precursors (e.g., agricultural waste, forestry residues, algae, and industrial by-products). These materials leverage hierarchical porosity, high specific surface area (often >2000 m²/g), tunable surface chemistry, and inherently sustainable sourcing to deliver exceptional capacitive performance. We detail the conversion pathways—including pyrolysis, physical/chemical activation, and hydrothermal carbonization—and their impact on the final carbon architecture. The electrochemical analysis covers specific capacitance (frequently reaching 200–400 F/g in aqueous electrolytes), energy density (5–10 Wh/kg), power density, and long-term cycling stability (>10,000 cycles). The review underscores the potential of biomass-derived carbons to provide a cost-effective, eco-friendly alternative to conventional fossil-based or synthetic carbons, thereby contributing to the circular economy. Challenges in consistency, scalability, and competitive energy density versus batteries are also addressed. The conclusion highlights future directions for optimizing performance through heteroatom doping, composite formation, and advanced device engineering.