Facile hydrothermal synthesis of flowerlike MnO2 constructed by ultrathin nanosheets for supercapacitors

Flowerlike manganese dioxide (MnO2) built up of ultrathin nanosheets was successfully prepared without any template or surfactant, using a facile hydrothermal route based on the redox reaction between ammonium iron (II) sulfate(NH4)(2)Fe(SO4)(2) 6H(2)O) and potassium permanganate (KMnO4), X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron miscroscopy (HRTEM) were used to characterize the prepared samples. Futhermore, the capacitive properties of flowerlike MnO2 were studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements. The specific capacitance is 189.3 F.g(-1) for flowerlike MnO2 at a scan rates of 2 mV.s(-1) in 1.0 mol.L-1 Na2SO4. The specific capacitance of flowerlike MnO2 electrode almost keeps immovability over 200 cycles at a current density of 3.0 A.g(-1.) Thus, the flowerlike MnO2 constructed by ultrathin nanosheets can be used as a candidate electrode material for supercapacitors.