Investigations on Electrochemical Activity of Polycarbazole/Cadmium Sulfide/Hematite Iron (III) Oxide (PCz/CdS/α‐Fe₂O₃) Nanocomposite Electrode for Supercapacitors

Abstract

A novel ternary polycarbazole/cadmium sulfide/hematite iron (III) oxide (PCz/CdS/α‐Fe2O3) nanocomposite was synthesized through in situ chemical polymerization method. The phase structure and morphology of PCz, PCz/CdS, PCz/α‐Fe2O3, and PCz/CdS/α‐Fe2O3 were analyzed using XRD and FESEM techniques. From HR‐TEM study, particle size of PCz/CdS/α‐Fe2O3 nanocomposite was found to be 68.09 nm. The chemical composition and the binding energy of the elements present in PCz/CdS/α‐Fe2O3 nanocomposite were examined through XPS. BET studies revealed the mesoporous nature of PCz/CdS/α‐Fe2O3 with a large surface area (35.51 m2 g−1) compared to PCz/α‐Fe2O3 (21.52 m2 g−1) and PCz/CdS (7.47 m2 g−1) nanocomposites. Cyclic voltammetric studies revealed the highest specific capacitance (634.14 Fg−1) of ternary PCz/CdS/α‐Fe2O3 electrode in KOH electrolyte in comparison to H2SO4 (49.44 Fg−1) and Na2SO4 (79.94 Fg−1) electrolytes at a scan rate of 3 mVs−1. Cyclic stability test indicated a high capacitive retentivity of PCz/CdS/α‐Fe2O3 (97%) electrode than PCz/CdS (90%) and PCz/α‐Fe2O3 (93%) electrodes after completion of 2000 cycles. From EIS, PCz/CdS/α‐Fe2O3 displayed a low ESR value (1.35 Ω) than the binary electrodes; the value increased slightly after the cyclic stability analysis. All these indicate the effectiveness of PCz/CdS/α‐Fe2O3 as a suitable electrode for supercapacitors.