The growing demand for energy storage solutions has necessitated the development of advanced materials with high efficiency, sustainability, and cost-effectiveness. This study explores the recycling of waste batteries into nitrogen-doped reduced graphene oxide (N-RGO) incorporated with boron nitride (BN) nanosheets for supercapacitor applications. The synthesis process involves a sustainable Electrochemical Exfoliation, Modified Hummer’s and simple sonication methods which enabling the recovery of valuable carbon-based materials from waste batteries and their functionalization with nitrogen. Electrochemical analysis of N-RGO/BN composite shows excellent specific capacitance and lower charge transfer resistance for three electrode configurations. In full cell, the device achieved excellent specific capacitance of 86 F g−1, specific energy of 12 Wh kg−1 and specific power of 200 W kg−1 with capacitance retention of 88 % and 95 % of coulombic efficiency even after 10,000 cycles in coin cell configuration. The results highlight the potential of recycling waste batteries into functional materials for sustainable energy storage systems, contributing to both environmental preservation and technological advancement. © 2025 Elsevier B.V., All rights reserved.