Single crystal nanorods of gamma-MnOOH with lengths up to hundreds of nanometers were successfully prepared employing a novel solvothermal process based on the redox reaction between potassium permanganate (KMnO4) and N. N-dimethyl ammonium formate (DMF) without extra surfactant or template. The as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and Fourier transformed infrared spectroscopy (FTIR). The electrochemical properties of gamma-MnOOH nanorods were investigated by cyclic voltammetry and galvanostatic charge-discharge performance measurements. Specific capacitance (C-s) calculated from the galvanostatic discharge curve was 131.9 F g(-1) for gamma-MnOOH nanorods at the current density of 0.5 A g(-1). The electrochemical experiment results demonstrate that gamma-MnOOH nanorods should be a good candidate as electrode material for supercapacitor. (C) 2011 Elsevier Inc. All rights reserved.