Recent Advances in Biomass‐Derived Carbon Electrodes for Supercapacitors: Green Synthesis, Multiheteroatom Doping, and Device‐Level Applications

ABSTRACT The growing demand for sustainable and high‐performance energy storage systems have accelerated intensive research into biomass‐derived carbon (BDC) materials as electrodes for supercapacitors (SCs). Owing to their natural abundance, renewability, intrinsic heteroatom content, and structural diversity, biomass precursors offer a versatile platform for designing ecofriendly carbon electrodes with tunable physicochemical properties. This review systematically presents the fundamental principles of SCs and highlights the unique advantages of BDCs in electrochemical energy storage. Various green synthesis strategies are critically discussed with emphasis on their roles in tailoring pore architecture, surface chemistry, and conductivity. Particular attention is devoted to multiheteroatom doping, which enhances charge storage through synergistic electrical double‐layer capacitance and pseudocapacitive contributions. Furthermore, the review correlates structure, morphology, and surface functionalization with electrochemical performance, providing insights into pore structure engineering and morphology performance relationships. Recent progress in electrode‐ and device‐level electrochemical performance, including symmetric and asymmetric SC configurations, is comprehensively evaluated. Finally, key challenges and limitations such as scalability, precursor variability, structure‐performance trade‐offs, and critically the poorly understood degradation mechanisms governing long‐term cycling stability are identified, and future prospects are outlined to guide the rational design of the next‐generation BDCs electrodes for sustainable SC applications.