Step-by-step assembled poly(3,4-ethylenedioxythiophene)/manganese dioxide composite electrodes: Tuning the structure for high electrochemical performance

A class of novel composite electrodes based on poly(3,4-ethylenedioxythiophene) (PEDOT) and manganese dioxide (MnO2) was assembled by step-by-step anodic deposition on nickel foam for super-capacitor application. The effect of the distribution and loading of PEDOT on the electrochemical performance of composite electrodes was studied carefully. Among these composite electrodes, the optimized PEDOT/MnO2/PEDOT sandwich electrode shows excellent capacitive behavior, and MnO2 species in the optimized sandwich electrode possesses a high specific capacitance of 487.5 F g(-1) at 1 A g(-1). Furthermore, an asymmetric supercapacitor cell with the optimized sandwich composite as positive electrode and active carbon (AC) as negative electrode also exhibits.outstanding performance at a cell voltage of 1.8 V in a 0.5 M Na2SO4 aqueous electrolyte. It has a high energy density of 30.2 Wh kg(-1) with a power density of 180 W kg(-1). And even at a high power density of 2.7 kW kg(-1), the asymmetric supercapacitor can deliver a high energy density of 13.1 Wh kg(-1). Moreover, the asymmetric supercapacitor displays impressive electrochemical cycling stability with 99.5% initial capacitance remained after 1000 continuous cycles. (C) 2012 Elsevier Ltd. All rights reserved.