A complete three-dimensionally nanostructured asymmetric supercapacitor with high operating voltage window based on PPy and MnO2

The development of novel functional nanostructures and the implementation of an asymmetric cell design are the key challenges to increase the electrochemical performance of aqueous based supercapacitors. In this manuscript complex three-dimensional electrode materials are nano-engineered based on free-standing open-ended core/shell nanotube arrays with tailored functions. Both the negative and positive electrode materials are designed and nanostructured individually, using an innovative material combination of Polypyrrole (PPy) and manganese oxide (MnO2). This asymmetric cell design increases the possible operating potential window to 1.7 V, which is a major leap to enhance the specific energy of supercapacitors. The prepared device exhibits a high specific energy of 27.2 Wh kg(-1) and a high specific power 24.8 kW kg(-1). (C) 2014 Elsevier Ltd. All rights reserved.