Si-containing 3D cage-functionalized graphene oxide grafted with Ferrocene for high-performance supercapacitor application: An experimental and theoretical study

In this work, graphene oxide sheets were functionalized with Octa(aminopropyl)silsesquioxane. Then, Octa(aminopropyl)silsesquioxane-functionalized graphene oxide (GO-Amine-SSQ) was grafted with Ferrocene through Friedel-Craft reaction. Structural properties of the prepared composite (GO-Amine-SSQ-Fc) were analyzed by XPS, FT-IR, XRD, Raman, SEM, TEM, and BET tests. Results confirmed the successful synthesis and high porosity. Next, the electrochemical properties of GO-Amine-SSQ-Fc were characterized by CV, GCD, and EIS techniques in the 3E system. The GO-Amine-SSQ-Fc electrode showed a specific capacitance of 574 F g−1 at 1 A g−1, retention capacitance of 90.1% after 10,000 charge-discharge cycles, low resistance, and efficient diffusion of ions. After confirming the excellent electrochemical performance of this electrode, a symmetric supercapacitor system (GO-Amine-SSQ-Fc//GO-Amine-SSQ-Fc) was tested by CV and GCD techniques, to determine practical application of system. GO-Amine-SSQ-Fc//GO- Amine-SSQ-Fc system recorded a specific capacitance of 304 F g−1 at 0.5 A g−1, retention capacitance of 92.5% over 10,000 charge-discharge cycles, and specific energy of 10.14 Wh kg−1 at a specific power of 500 W kg−1. Also, the results of computational methodology show that the interaction of SSQ, Fc and GO layer in GO-Amine-SSQ-Fc composite, makes it effective as an electrode material for supercapacitors. This excellent performance, as a result of the unique structure of Amine-SSQ groups and the superior electrochemical behavior of Ferrocene groups, suggests that GO-Amine-SSQ-Fc composite has great potential for energy storage devices.