A highly porous polyaniline-graphene composite used for electrochemical supercapacitors

Abstract

A polyaniline (PANI)-porous graphene (PGR) hybrid material with high capacitive performance was synthesized through electropolymerization of aniline on the PGR. The microstructure and morphologies of the PANI-PGR were characterized by field emission scanning electron microscopy, while electrochemical behaviors were measured by cyclic voltammetry and galvanostatic charge-discharge. The effects of aniline and PGR concentrations and polymerization cycles on electrochemical performances of the PANI-PGR were investigated. The results demonstrated that the prepared PANI0.05-PGR1.25-15 (0.05 M aniline, 1.25 mg·ml-1 PGR and 15 polymerization cycles) showed the highest specific capacitance of 1209 F·g-1 at 0.2 A·g-1. The specific capacitance of the obtained PANI-PGR was higher compared with other PANI materials, such as graphene (GR)-wrapped PANI nanofiber, single walled carbon nanotube/PANI, and GR-PANI nanoworm composites. The PANI0.05-PGR1.25-15 also displayed good cycle stability, retaining 92% of the initial capacitance after 1000 cycles of charge-discharge. The excellent capacitive properties were attributed to large specific surface area of the PGR and good pseudocapacitive properties of PANI.