Boosting charge transfer and cycling durability via B, N co-doping in carbon dots for efficient energy storage

The increasing demand for high-performance and sustainable energy storage systems has accelerated the development of advanced carbon-based nanomaterials. In this work, boron- and nitrogen-doped carbon dots (CDs) were synthesized via a facile solvothermal method route using citric acid, aniline, and boric acid as carbon, nitrogen, and boron sources. FTIR, UV-Vis, HRTEM, and XPS analyses confirmed successful heteroatom doping, uniform particle sizes of 12–15 nm, and abundant surface functional groups favorable for electrochemical activity. The electrochemical performance of the carbon dots electrode was evaluated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy in a three-electrode system with 2 M KOH electrolyte. The electrode delivered a high specific capacitance of 351 F g−1 at 1 A g−1, excellent rate capability, and remarkable cycling stability, retaining 97% capacitance after 10000 cycles. The low charge-transfer resistance (0.86 Ω) indicates enhanced ion and electron transport, highlighting the potential of doped CDs for next-generation supercapacitors.