This study introduces an efficient potentiostatic method to enhance the energy storage performance of polyaniline (PN) by synthesizing PN@ZnO (PNZ), PN@Fe2O3 (PNF), and PN@ZnFe2O4 (PNZF) hybrid electrodes with defined porous morphology. The precise selection and control of the working potential during electro-polymerization and metal oxide integration using the linear sweep voltammetry was key for synthesizing the polymer hybrid electrodes reproducible and with defined composition and structure. The PNZF electrode demonstrated the highest specific capacitances of 816 F g-1 and 791.3 F g 1 at a scan rate of 5 mV s-1 and 1.0 A g-1 current density, along with high power density and energy density of 1058.4 W kg-1 and 136.4 Wh kg 1, and with excellent stability retaining 90 % over 4000 cycles. We could attribute the excellent performance to a low charge transfer resistance of 25.0 Ω, a predominantly surface-controlled charge storage mechanism, and a porous morphology with uniform distribution of ZnFe2O4 particles in the polymer network, all resulting from the electrochemical synthesis method. Our study provides valuable and new insights into the structural, optical, and electrochemical properties of PN composites, particularly PNZF.
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Figure_1: (a) Linear sweep voltammetry (LSV) of aniline, and (b) cyclic voltammetry of ZnO, Fe2O3 and ZnFe2O4 in the synthesis precursor solution.
Figure 2: Current to time response (I-t) profiles during synthesis of (a) PN, (b) PNZ, (c) PNF and (d) PNZF.
Figure 4: XRD spectra of (a) PN synthesized by CV during parameter identification, (b) PN synthesized by CA, (c) ZnO, (d) PNZ, (e) Fe2O3, (f) PNF, (g) ZnFe2O4, (h) PNZF.
Figure 5: FT-IR spectra of (a) PN and its composites, (b) ZnO, Fe2O3 and ZnFe2O4.
Figure 6: UV/Vis spectra of (a) PN and its composites and (b) ZnO, Fe2O3, and ZnFe2O4.
Figure 7: Cyclic voltammograms of (a) PN, (b) PNZ, (c) PNF, and (d) PNFZ at different scan rates. Potentials are referred to SCE (KClsat. in H2O).
Figure 8: Comparison of PN and its composites for (a) CV measurements at a scan rate of 5 mV s 1, (b) the calculated specific capacitances of PN, PNZ, PNF and PNZF for different scan rates, (c) the calculated capacitance retentions for 4,000 cycles at 30 mV s-1.
Figure 9: GCD experiments at different current densities of (a) PN, (b) PNZ, (c) PNF, and (d) PNZF. (e) Comparison of the specific capacitances of PN and its composites at different current densities.
Figure 10: EIS spectra of PN, PNZ, PNF, and PNFZ.
