Unlocking the Eco‐Friendly Approaches of Batteries and Supercapacitors in the Present Time and Future Directions

ABSTRACT The growing global demand for efficient and eco‐friendly energy storage technologies has accelerated research on advanced functional materials for batteries and supercapacitors. This review presents a comprehensive analysis of materials used in both energy storage systems, emphasizing the relationship between material composition, structural characteristics, and electrochemical performance. Different types of electrode materials, like transition metal oxides, carbon‐based nanomaterials, conducting polymers, and emerging two‐dimensional materials, are systematically discussed with respect to their synthesis strategies, interfacial characteristics, and energy storage mechanisms. Moreover, the review critically examines the major challenges associated with existing electrode materials. Furthermore, recent developments in flexible, wearable, and solid‐state energy storage devices are highlighted because of their increasing importance in portable electronics and smart technologies. Finally, future perspectives focusing on scalable production methods, low‐cost fabrication, environmental sustainability, and multifunctional high‐performance materials are discussed to support the advancement of next‐generation sustainable energy storage systems.