A high-performance covalently bonded self-doped polyaniline–graphene assembly film with superior stability for supercapacitors

Abstract

In this study, a robust high-performance polyaniline-modified graphene electrode is successfully used to assemble a supercapacitor. Graphene is covalently bonded to self-doped polyaniline (SPANI) and used in supercapacitors, and 4-aminobenzoic acid-modified graphene (ABF-G) sheet materials are first bonded to an aniline functional group at graphene edges. Then, aniline, o-aminobenzene sulfonic acid monomers, and an oxidising agent are added into the ABF-G aqueous dispersion to achieve polymerisation on the surface of ABF-G. This covalently bonded SPANI-modified ABF-G (SPANI-ABF-G) thin-film electrode material is then used for fabricating supercapacitors. A Raman spectrometer, a scanning electron microscope, a secondary ion mass spectrometer, an X-ray electron photon spectrometer, and a specific surface area analyser are used to characterise this film. The supercapacitor with the proposed SPANI-ABF-G electrodes exhibits a high specific capacitance value of 642.6 F/g for charging and discharging at a current density of 1 A/g. After 5000 cycle-life testing, this supercapacitor exhibits a charging and discharging capacitance retention of 100% and 98.13% at a current density of 1 and 2 A/g, respectively. These capacitance retentions are higher than those of supercapacitors with conductive polymers electrodes. The results prove that electrode materials prepared using covalently bonded graphene and PANI can considerably improve supercapacitor performance.