Exploring the charge storage mechanism in high-performance Co@MnO2-based hybrid supercapacitors using Randles–Ševčík and Dunn’s models

• Published in: Journal of applied electrochemistry Vol. 54; no. 1; pp. 65 - 76
• Main Authors: Afzal, Amir Muhammad, Muzaffar, Nimra, Iqbal, Muhammad Waqas, Dastgeer, Ghulam, Manzoor, Alina, Razaq, Muhammad, Wabaidur, Saikh Mohammad, Al-Ammar, Essam A., Eldin, Sayed M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2024; Springer Nature B.V
• Subjects: Activated carbon; Capacitance; Chemistry; Chemistry and Materials Science; Electrochemical analysis; Electrochemistry; Electrodes; Energy storage; Industrial Chemistry/Chemical Engineering; Manganese dioxide; Physical Chemistry; Research Article; Sol-gel processes; Storage systems; Supercapacitors; Power density; Hybrid supercapacitors; Energy density; Co@MnO; Dunn’s models; Specific capacity
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-023-01939-3

Hybrid supercapacitors are energy storage technology offering higher power and energy density as compared to capacitors and batteries. Cobalt-doped manganese oxide (Co@MnO 2 ) was synthesized using an easy and affordable sol–gel process and measured the electrochemical properties. A value of the specific capacity of 1141.42 Cg −1 was obtained which was larger in comparison to the reference sample (MnO 2  = 673.79 Cg −1 ). The value of the specific capacitance was achieved 1902 Fg −1 . To design a hybrid supercapacitor device, Co@MnO 2 was used as the positive electrode and the activated carbon was employed as the negative electrode in two-electrode assembly. According to calculations, the measured value of the specific capacitance of Co@MnO 2 was 713.25 Fg −1 . The charge storage mechanism is supported with the help of Randles–Ševčík and Dunn’s models. The estimated value of energy and power densities were 3200 Wh kg −1 and 24 Wkg −1 , respectively. The stability of this device was checked by putting it to 1000 charging and discharging cycles, and it retained 86% of its initial capacity. Our result provides a platform for enhancing the functionality of energy storage systems. Graphical abstract