Facile preparation of MnO2@C composite nanorods for high-performance supercapacitors

Abstract

Novel MnO2@C composite nanorods were successfully prepared by a facile solvothermal method. The results showed that a uniform carbon layer was formed around the MnO2 nanorods. The carbon layer provided a highly conductive pathway to boost the charge transport involved during the capacitance generation. The electrochemical properties of MnO2@C composite nanorods were investigated by cyclic voltammetry and galvanostatic charge–discharge. The composites as electrode materials of supercapacitors exhibited high specific capacitance (295 F/g) compared with MnO2 nanorods (149 F/g) with a wide operation window (0–1.0 V). The electrochemical impedance spectroscopic studies showed the charge-transfer resistance (Rct) of the MnO2@C composite nanorods (1.10 Ω) was much lower than that of pure MnO2 (2.53 Ω). Moreover, the MnO2@C composite nanorods exhibited excellent cycling behavior with no more than 5 % capacitance loss after 2000 cycles. These results indicated that the MnO2@C composite nanorods could be a promising electrode material for high-performance electrochemical capacitors.