Supercapacitive behaviors and their temperature dependence of sol-gel synthesized nanostructured manganese dioxide in lithium hydroxide electrolyte

In the present work, a nanostructured manganese dioxide material was synthesized by a sol-gel method starting with manganese acetate (MnAc2 center dot 4H(2)O) and citric acid (C6H8O7 center dot H2O) raw materials, and characterized by X-ray diffraction, infrared spectroscopic and transmission electron microscope techniques. The electrochemical properties and the influence of temperature on supercapacitive behaviors of the nano-MnO2 electrode in 1 M LiOH electrolyte were investigated using electrochemical methods. Experimental results show that the MnO2 electrode can exhibit an excellent pseudocapacitive behavior in 1 M LiOH electrolyte, and a high specific capacitance of 317 F g(-1) can be obtained at a charge/discharge current rate of 100 mA g(-1) and at the temperature of 25 degrees C. We found that temperature has a crucial influence on the discharge specific capacitance of the electrode. The specific capacitance at 25 degrees C is higher than that at 15 or 35 degrees C. (c) 2007 Elsevier B.V. All rights reserved.