Remarkably enhanced performances of novel polythiophene-grafting-graphene oxide composite via long alkoxy linkage for supercapacitor application

A long alkoxy substituted polythiohene poly[3-(2-(2-(2-(2-(diethanolamino) ethoxy) ethoxy) ethoxy) ethoxy) thiophene] (PD4ET) was chemically grafted to the graphene oxide (GO) nanosheets via esterification reaction to give a novel PD4ET-g-GO nanocomposite. The formation of a bridge between PD4ET and GO is confirmed and characterized by fourier transform infrared (FT-IR), X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS). The morphological details and elemental compositions analysis indicates that the PD4ET is successfully grafted to the edge of GO sheets with a few nanometers thickness. More significantly, PD4ET-g-GO electrode exhibit enhanced electrochemical performance with a maximum specific capacitance of 971 F/g at a current density of 1 A/g using a three-electrode system, which is much higher than that of each individual component and the physical mixture. High energy and power density is achieved up to 66.11 Wh/kg and 350 W/kg and of 38.11 Wh/kg and 7000 W/kg, respectively. The cycling stability investigation showed that PD4ET-g-GO based capacitor can preserve 98% of its initial capacitance within 10000 consecutive charge-discharge cycles, suggesting a good cycling stability for the composite electrodes. Furthermore, the fabricated solid-state super-capacitor device shows remarkable electrochemical performance, which can power the red LED diode in series connection. (C) 2019 Elsevier Ltd. All rights reserved.