Soft- to network hard-material for constructing both ion- and electron-conductive hierarchical porous structure to significantly boost energy density of a supercapacitor

Abstract

Soft-material PEDOT is used to network hard Co3O4 nanowires for constructing both ion- and electron-conductive hierarchical porous structure Co3O4/PEDOT to greatly boost the capacitor energy density than sum of that of plain Co3O4 nanowires and PEDOT film. Specifically, the networked hierarchical porous structure of Co3O4/PEDOT is synthesized and tailored through hydrothermal method and post-electrochemical polymerization method for the PEDOT coating onto Co3O4 nanowires. Typically, Co3O4/PEDOT supercapacitor gets a highest areal capacitance of 160mFcm−2 at a current density of 0.2mAcm−2, which is about 2.2 times larger than the sum of that of plain Co3O4 NWs (0.92mFcm−2) and PEDOT film (69.88mFcm−2). Besides, if only PEDOT as active mass is counted, Co3O4/PEDOT cell can achieve a highest capacitance of 567.21Fg−1, this is the highest capacitance value obtained by PEDOT-based supercapacitors. Furthermore, this soft-hard network porous structure also achieves a high cycling stability of 93% capacitance retention after the 20,000th cycle. This work demonstrates a new approach to constructing both ion and electron conductive hierarchical porous structure to significantly boost energy density of a supercapacitor.