Modified iron doped polyaniline/sulfonated carbon nanotubes for all symmetric solid-state supercapacitor

•A novel iron doped polyaniline over the surface of sulfonated carbon nanotubes was prepared.•The material followed by Freeze-Drying treatment and showed surface area 397.79 m2 g−1.•The symmetric solid-state supercapacitor prepared from Freeze-Dried sample.

Electrode materials based on iron doped polyaniline (Fe-PANI) over the surface of sulfonated multi-walled carbon nanotubes (s-MCNTs) followed by freeze-drying treatment (FD-Fe-PANI@s-MCNTs) are dedicated for high performance electrochemical energy storage applications. The structure, morphology and thermal properties of the studied electrode samples are measured with different characterizing techniques. The N2 sorption isotherm for (FD-Fe-PANI@s-MCNTs) shows high specific surface area 397.79 m2 g−1 calculated by Brunauer-Emmett-Teller (BET) method after the freeze-drying treatment.The electrochemical properties of the electrode samples are assessed by cyclic voltammetry and galvanostatic charge/discharge testes in the 1 M H2SO4 aqueous electrolyte. The (FD-Fe-PANI@s-MCNTs) electrode with this high surface area shows high specific capacitance of 2105.64 F g−1at 1 A g−1. The symmetric solid-state supercapacitor device (SCs) based on (FD-Fe-PANI@s-MCNTs) electrode gave a specific capacitance of 776.85 F g−1 at 1 A g−1, energy density 13.55 Wh kg−1, power density 177.50 W kg−1 and exhibit rate capability (≈59% retention at 20 A g−1). Furthermore, the symmetric supercapacitor device shows good cycling stability (91.6%) after 500 cycles at a scan rate 200 mV s−1, suggesting the potential application of (FD-Fe-PANI@s-MCNTs) for energy storage devices.

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