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

¹ Department of Chemistry, College of Science, University of Bisha - Bisha 61922, Saudi Arabia
² Department of Physical Sciences, Physics Division, College of Science, Jazan University Jazan 45142, Saudi Arabia
³ Department of Chemistry, College of Science, Taif University - Taif 21944, Saudi Arabia
⁴ Department of Physics, College of Science, University of Bisha - P.O. Box 551, Bisha 61922, Saudi Arabia
⁵ Department of supportive requirements, University of Technology and Applied Sciences - Shinas 324, Oman
⁶ Department of Chemistry, College of Science, Umm AlQura University - P.O. Box 715, Mecca, 21955, Saudi Arabia
⁷ Saudi Railway Research Group, Department of Mechanical Engineering, College of Engineering, Shaqra University Dawadmi, Riyadh 11911, Saudi Arabia
⁸ Department of Physics, College of Science in Yanbu, Taibah University - Yanbu Governorate, Saudi Arabia
⁹ Department of Laser Sciences and Interactions, National Institute of Laser Enhanced Sciences, Cairo University Giza, Egypt

Received: 18 December 2025
Accepted: 10 February 2026

Abstract

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.