Facile preparation of polyaniline covalently grafted to isocyanate functionalized reduced graphene oxide nanocomposite for high performance flexible supercapacitors

Graphene oxide nanosheets (GO) is simultaneously reduced and functionalized by isophorone diisocyanate (IPDI), followed by grafting polyaniline (PANI) in mild condition to produce a novel PANI-IPDI-rGO composite useful for supercapacitors application. The structural and morphological analysis indicates only a few nanometers thickness of emeraldine salt form of PANI layer is anchored to the surface of rGO sheets. On account of high pseudo-capacitance of PANI, high conductivity of graphene scaffolds and the synergistic effect between the components, the PANI-IPDI-rGO electrode shows dramatically optimized gravimetric specific capacitance of 1415 F/g without compromising rate capability, which is much higher than that of PANI/rGO non-functionalized composites. In addition, the assembled all-solid-state supercapacitor device based on PANI-IPDI-rGO positive electrode exhibits high electrochemical performance, such as a remarkable gravimetric specific capacitance of 485 F/g (9.1 F/cm(3)), superior energy storage capacitance with maximum energy density of 113.8 Wh/kg (2.07 mW h/cm(3)), and excellent capacitance retention of 95 % after 2000 consecutive charge-discharge cycles. Preliminary results reveal that the effective synthesis strategy paves an alternative avenue for nanostructure hybrid electrode materials in wearable and portable energy storage systems.