Polyaniline-modified renewable biocarbon composites as an efficient hybrid electrode for supercapacitors

Abstract

Polyaniline-modified renewable biocarbon (ACPANI) composites were prepared via static low-temperature in situ polymerization of aniline monomers on the biomass-based porous biocarbon (AC) that was derived from watermelon rind. In the ACPANI composites, the AC biocarbon was served as a three-dimensional supporting skeleton for polyaniline (PANI) to provide a large accessible surface area, and PANI was used to improve their electrochemical performances. The porous AC biocarbon was coated with nanofibrous arrays of PANI via electrostatic interaction and van der Waals forces. The ACPANI-2 composite that obtained with an AC/aniline mass ratio of 20:80 exhibited an excellent electrochemical performance as a hybrid electrode for supercapacitor. A superb specific capacitance of 520 F g−1 for ACPANI-2 was achieved at a current density of 1 A g−1, and a high cycling stability with a retention rate of capacitance of 71.2% after 5000 cycles was confirmed. Furthermore, an asymmetric supercapacitor using ACPANI-2 as a positive electrode assembled with the AC negative electrode acquired a cell voltage of 1.4 V and a high energy density of 29.3 Wh kg−1. Therefore, the ACPANI composite is suggested to be a promising candidate for electrochemical supercapacitor.