Electrochemical performance of polyaniline-coated γ-MnO2 on carbon cloth as flexible electrode for supercapacitor

Abstract

Carbon cloth (CC) based supercapacitor is considered as one of the most promising electrode materials for flexible supercapacitor due to their excellent flexibility and electrochemical properties. In this paper, a low-cost ternary hybrid material polyaniline-coated γ-MnO2/carbon cloth (PANI@γ-MnO2/CC) is synthesized via facile hydrothermal and in-situ electrochemical polymerization reactions for superior supercapacitor electrode materials. Flexible conductive CC can not only be used as a scaffold for the growth of γ-MnO2 and PANI but also can be used as a carbon source for generation γ-MnO2. The structure and electrochemical properties of PANI@γ-MnO2/CC composite are investigated via different testing techniques. The coating PANI layer on the surface of γ-MnO2@CC with a three-dimensional hierarchical structure provides high electroactive surface area and accelerates the ion diffusion and electron transfer. Due to synergistic effects between the components, the flexible PANI@γ-MnO2/CC composite displays a high specific capacitance of 1105 mF cm−2 (371.4 C g−1) at a current density of 1 mA cm−2 in 0.5 M H2SO4 aqueous electrolyte and long cycle stability for 2000 cycles with 86.35%, as well as good rate performance 72.3% capacitance retention from 1 to 10 mA cm−2. Furthermore, flexible asymmetric supercapacitor (FASCs) based on PANI@γ-MnO2/CC and PVA-H2SO4 gel electrolyte have been fabricated and it has shown the energy density of 10.4 mW cm−3 at a power density of 1.5 mWh cm−3. The ease of preparation and excellent energy storage capability indicates that the PANI@γ-MnO2/CC composite could be a promising electrode material for supercapacitor application.