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

Abstract

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 supercapacitor 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 487.5Fg−1 at 1Ag−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 1.8V in a 0.5M Na2SO4 aqueous electrolyte. It has a high energy density of 30.2Whkg−1 with a power density of 180Wkg−1. And even at a high power density of 2.7kWkg−1, the asymmetric supercapacitor can deliver a high energy density of 13.1Whkg−1. Moreover, the asymmetric supercapacitor displays impressive electrochemical cycling stability with 99.5% initial capacitance remained after 1000 continuous cycles.