MnO2/polyaniline hybrid nanostructures on carbon cloth for supercapacitor electrodes

A facile two-step strategy is developed for synthesis of MnO2/polyaniline (PANI) hybrid nanostructures on carbon cloth (CC). Vertically aligned PANI nanofiber arrays were firstly grown on CC via chemical oxidative polymerization, and MnO2 nanoparticles were then deposited on the surface of PANI nanofibers via redox reaction between PANI and KMnO4 solution. Structural and morphological characterizations of composites were investigated by FESEM, Raman, and XPS techniques, respectively. Electrochemical performance of the composites as supercapacitor electrode materials was evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. The results demonstrate that the morphology and areal specific capacitance of the MnO2/PANI/CC composite vary with MnO2 deposition time. The ternary composite with 6 h MnO2 deposition exhibits a high areal capacitance of 1.56 F cm−2 at the scan rate of 10 mV s−1 and 0.99 F cm−2 at a current density of 2 mA cm−2 and still maintains 88.1 % of the original capacitance after 1000 charge-discharge cycles at a large current density of 10 mA cm−2.The excellent performance is due to the synergistic effect from the combination of two active pseudo materials and 3D conductive CC backbone. This study further highlights the importance of optimal design and control of material structures in supercapacitor applications.