Agricultural waste derived biomass electrode material: recent advancements on processing, synthesis, properties and electrochemical energy storage application

Agricultural biomass offers a sustainable and cost-effective precursor for synthesizing activated carbon (AC) electrodes in energy storage systems, addressing both the global energy crisis and the environmental challenges of fossil-based materials. Biomass-derived carbons have gained increasing attention for supercapacitor applications due to their natural abundance, tunable porosity, and excellent electrochemical properties. This review critically examines recent progress in processing routes, activation strategies, and structure-property relationships of AC derived from agricultural wastes. Emphasis is placed on emerging approaches such as heteroatom doping, template-assisted activation, and composite design that enhance energy density and cycling stability. The novelty of this work lies in its integrated analysis of synthesis–performance correlations and the identification of future pathways toward scalable, green production of high-performance, biomass-derived AC electrodes for next-generation supercapacitors.