Ferrocene surface-modified Fe3O4 nanoparticles as prominent electrode material for supercapacitor application

Supercapacitors (SCs) have gained significant interest in electronic devices due to their longer cycle life and high power density. Grafting functional materials onto magnetite nanoparticles is considered as a potential strategy for designing diverse functional nanoparticles. So, applying various grafting strategies with organic and organometallic materials is highly desired. Herein, we present the successful surface modification of Fe3O4 nanoparticles by the Ferrocene (Fc) moiety through a simple hydrosilylation route. Firstly, Fe3O4 nanoparticles were prepared via the aqueous co-precipitation of FeCl3·6H2O and FeC12·4H2O, followed by the addition of ammonium hydroxide. Then magnetite nanoparticles were coated with silica through the Stöber method, which enhanced the dispersity of Fe3O4@SiO2 nanoparticles. After that, the nanoparticles were modified with triethoxyvinylsilane as a coupling agent for functionalizing the surface of Fe3O4@SiO2 with vinyl groups. Finally, (4-Ferrocenylbutyl)dimethylsilane was grafted on the surface of magnetite nanoparticles via a hydrosilylation approach. The obtained nanomaterials were thoroughly characterized by appropriate techniques, including FT-IR, FE-SEM, EDX-MAP, XRD, VSM, and BET. All nanomaterials are investigated as electrode materials for SCs. The Fe3O4@SiO2@Fc nanoparticles possess a specific capacity of 161 mAh g−1 at 2.5 A g−1, while pure Fe3O4 shows 71 mAh g−1 at the same current density. Also, the Fe3O4@SiO2@Fc electrode shows high energy and power densities of 96.6 Wh Kg−1, and 5896 W Kg−1, respectively, and excellent electrochemical cycling performance (84.6 %) after 3000 charge/discharge cycles. Based on our results, Fe3O4@SiO2@Fc exhibits exceptional electrochemical performances, thus, the proposed method can be applied to construct high-performance electrode materials for energy storage devices.