Developing advanced materials are vital to maximizing supercapacitor performance potential. This study examined Co-

Zn-

and Pb-doped ZIF-8@ZIF-67 nanocomposites for enhanced supercapacitor performance. The structural

morphological

optical

and electrochemical properties were analyzed using X-ray diffraction

scanning electron microscopy (SEM)

ultraviolet-visible spectroscopy

Fourier transform infrared (FTIR) spectroscopy

and cyclic voltammetry (CV)

respectively. X-ray diffraction analysis shows that the hybridization and doping of the nanocomposites were successful. The SEM images revealed a distinct morphological difference with Pb-doped composites demonstrating a combination of two different kinds of nanoparticles

while the energy-dispersive spectroscopy (EDS) analysis shows the successful incorporation of the dopants in the hybridized framework. In addition

optical analysis revealed improved absorbance and reduced band gap values ranging from 2.35 eV

1.95 eV

and 1.58 eV for Co-

Zn-

and Pb-doped composites

respectively. Electrochemical analyses showed a pseudocapacitive behavior as demonstrated by the redox peaks in the CV plots. As the scan rate increases

the specific capacitance decreases. At 5 mV/s

Co-

Zn-

and Pb-doped electrodes have estimated specific capacitances of 987.50 F/g

962.50 F/g

and 969.32 F/g

respectively. The low charge transfer resistance observed in the Nyquist plot suggested excellent capacitive performance. Based on the galvanostatic charge- discharge testing

Pb-doped ZIF-8@ZIF-67 demonstrated the highest specific capacitance of 428.63 F/g and energy density of 2.366 Wh/kg at 2.0 A/g. The Co/ZIF-8@ZIF-67 electrode demonstrated the highest power density of 8969.98 W/kg

while Zn/ZIF-8@ZIF-67 gave the maximum capacitance retention of 85.2% after 4800 cycles. According to these results

hybrid ZIF-8@ZIF-67 nanocomposites

especially the Pb-doped varieties

show potential for energy storage devices.