Facile synthesis of new hybrid electrode material based on activated carbon/multiwalled carbon nanotubes@ZnFe2O4 for supercapacitor applications

Abstract

A new hybrid composite of activated carbon (AC)/multiwalled carbon nanotubes (MWCNTs)-ZnFe2O4 has been prepared by the modest and low-cost method for its application as supercapacitor electrode material. The carbon-based composite electrode gives excellent cycle stability with moderate capacitance. So the capacitance of carbon-based composite electrode could be further improved by incorporating metal oxides as they involve reversible redox reaction. In this regard, zinc ferrite (ZnFe2O4) among various metal oxides is being considered as important additive material towards supercapacitor (SC) applications owing to its excellent physical and chemical properties. Hence, ZnFe2O4 is integrated with the carbon composite of MWCNTs and AC for better SC performance and cycle stability. The composite has resulted in maximum specific capacitance of 613 F/g at 5 mV/s when measured from cyclic voltammetry (CV) in 3 M KOH electrolyte. The measurement from galvanostatic charge–discharge (GCD) on synthesised composite has shown capacitance of 609 F/g at 1 A/g and that implying the significant storage performance of the prepared hybrid material. The stability, which is vital for the application of the composite, has been subjected for stability test and found that it retained 91% of the capacitance even after 10,000 cycles. Further, the synthesised materials have been characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH). The variation of current as a function of the applied voltage was analysed by current–voltage (I-V) measurements. These results suggest that the prepared composite can proficiently serve as a reliable choice for the electrode material for high-performance supercapacitor applications.