Design and Preparation of Graphene/FeO Nanocomposite as Negative Material for Supercapacitor

The development of high specific capacitance electrode materials with high efficiency, scalability and economic feasibility is significant for the application of supercapacitors, however, the synthesis of electrode material still faces huge challenges. Herein, graphene(G)/FeO nanocomposite was prepared via a simple hydrothermal method connected with subsequent thermal reduction process. Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) results showed rod-like FeO nanoparticles were prepared and well-dispersed on graphene layers, providing a rich active site and effectively buffering the aggregation of FeO nanoparticles in the process of electrochemical reaction. The specific capacitance of the obtained G/FeO nanocomposite as negative electrode for supercapacitor was 378.7 F/g at the current density of 1.5 A/g, and the specific capacitance retention was 88.76% after 3000 cycles. Furthermore, the asymmetric supercapacitor(ASC) was fabricated with G/FeO nanocomposite as negative electrode, graphene as positive electrode, which achieved a high energy density of 64.09 W·h/kg at a power density of 800.01 W/kg, maintained 30.07 W·h/kg at a power density of 8004.89 W/kg, and retained its initial capacitance by 78.04% after 3000 cycles. The excellent result offered a promising way for the G/FeO nanocomposite to be applied in high energy density storage systems.