Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate/magnesium oxide (PEDOT: PSS/MgO) nanohybrids infused with zinc (Zn) and cadmium (Cd) were synthesized using a co-precipitation method. Structural and morphological analyses using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR) confirmed successful incorporation of dopants and formation of the composite structure. Zn-, and Cd- doped PEDOT: PSS/MgO showed a specific capacitance of 146 Fg⁻¹ and 204 Fg⁻¹ at 10 mVs⁻¹, while galvanostatic charge–discharge measurements showed 15.2 and 27.5 Fg-1 at 0.25 Ag-1 indicating diffusion limitations at higher current densities. The charge transfer resistance of Zn-, and Cd- doped PEDOT: PSS/MgO showed 12.8 Ω and 10.5 Ω showing that Cd- doped PEDOT: PSS/MgO exhibits a lower value suggesting lower charge transfer resistance and faster electron transport at the electrode–electrolyte interface. The Cd-doped electrode produced an open-circuit voltage of 1.33 V and effectively powered a red LED, indicating practical applicability. Density Functional Theory (DFT) simulations further validated that Cd doping reduces the HOMO–LUMO energy gap (2.64 eV) and facilitates charge transfer by reinforcing Cd–O and Cd–Mg interactions. The integration of experimental and theoretical investigations confirms that Cd-doped PEDOT: PSS/MgO is a durable electrode material, providing enhanced charge transport, elevated energy density, and prolonged electrochemical stability for next-generation supercapacitors.
Goyal et al. (Wed,) studied this question.