Synergetic Electrochemical Behavior of NiO and Activated Carbon Composites for Advanced Supercapacitors
Moataz G. Fayed, Delvin Aman, Saad G. Mohamed
Abstract
Abstract Nickel oxide (NiO) nanoparticles were prepared using the co-precipitation method, and then activated carbon (AC) powder was blended with NiO with percentages of 25, 50, and 75%. X-ray diffraction patterns confirmed the formation of both NiO and NiO/AC nanocomposite structures. The NiO and NiO/AC nanocomposite powders were also fully characterized by Brunauer–Emmett–Teller (BET), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), which evidenced that the nanoparticles were uniformly distributed with the AC. The NiO and NiO/AC nanocomposite powders were investigated as supercapacitor electrode materials in a 6 M KOH aqueous solution. NiO nanoparticles electrode delivered a specific capacitance of 235 F g − 1 at a current density of 1 A g − 1 . In comparison, it was found that the AC50 (NiO/AC 50/50%) nanocomposite possessed the best electrochemical performance. It achieved specific capacitances of 325 F g − 1 and 215 F g − 1 at current densities of 1 and 5 A g − 1 , respectively. For practical application, the AC50 nanocomposite coin cell was assembled in 1 M TEABF 4 /PC organic electrolyte with good electrochemical performance. It delivered a specific capacitance of 72 F g − 1 at 1 mA g − 1 . It demonstrates remarkable electrochemical reversibility with 99.3% coulombic efficiency and 89.9% capacitance retention after 4000 cycles at the current density of 5 mA g − 1 . It also reveals a high specific energy of 62.5 Wh kg − 1 and a specific power of 638 W kg − 1 at a current density of 0.5 A g − 1 . Still, it exhibits a specific energy of 8.7 Wh kg − 1 and a specific power of 6944 W kg − 1 at a current density of 5 A g − 1 , estimating this material’s potential for use in supercapacitors.