A novel concept of hybrid capacitor based on manganese oxide materials

A novel asymmetric hybrid capacitor using LiMn2O4 and manganese oxide (MnO2)/carbon nanotube (CNT) nanocomposite as the positive and negative electrode materials, respectively, and 1 M LiClO4 in propylene carbonate (PC) as the electrolyte has been developed. To the best of our knowledge, this is the first reported assembly of an asymmetric hybrid capacitor with metal oxides for both electrode materials, and, especially, with MnO2 as the negative electrode material. The discharge profile of the asymmetric hybrid capacitor shows a typical capacitive behavior with a linear slope. The asymmetric hybrid capacitor was able to deliver a specific energy as high as 56 Wh/kg at a specific power of 300 W/kg, based on the total weight of LiMn2O4 and MnO2/CNT nanocomposite in both electrodes. These results clearly demonstrated a superior performance of this new type of capacitor with a higher specific energy compared to other types of asymmetric hybrid capacitors. (C) 2007 Elsevier B.V. All rights reserved.